Omar Khayyam

2.1. Birth and Early Life

Omar Khayyam was born in Nishapur, a prominent metropolis in the Greater Khorasan province of Iran, on May 18, 1048. His full name, as found in Arabic sources, was Abu'l Fath Omar ibn Ibrahim al-Khayyam. The designation Khayyam means 'tent-maker' in Arabic, leading to the common assumption, though open to doubt, that his ancestors were involved in this trade. The historian Bayhaqi, who knew Khayyam personally, recorded details of his horoscope, stating he was "Gemini, the sun and Mercury being in the ascendant," which helped modern scholars pinpoint his birth date.

Khayyam spent his early life in Nishapur, which was a significant center for the Zoroastrian religion before becoming a major city in the Seljuk Empire. His exceptional talents were recognized early by his tutors, who sent him to study under Imam Muwaffaq Nishaburi, regarded as the greatest teacher in the Khorasan region. Muwaffaq Nishaburi tutored children of the highest nobility, and Khayyam developed a strong, lasting friendship with him.

2.2. Education and Mentorship

Khayyam received extensive scholarly training, studying science, philosophy, mathematics, and astronomy in Nishapur. It is also suggested that he might have studied with Bahmanyar, a notable disciple of Avicenna. Around 1068, he traveled to the province of Bukhara, where he frequently visited the renowned library of the Ark. In approximately 1070, he relocated to Samarkand, where he began composing his influential Treatise on Algebra under the patronage of Abu Tahir Abd al-Rahman ibn ʿAlaq, the governor and chief judge of the city. The Karakhanid ruler Shams al-Mulk Nasr received Khayyam with great honor, seating him beside him on his throne.

A famous, though historically doubted, tradition known as the "Three School Friends" states that Khayyam, Nizam al-Mulk (who would become a powerful vizier), and Hassan-i Sabbah (the future leader of the Order of Assassins) were all students under Imam Muwaffaq Nishaburi. The legend claims they made a pact to share their fortunes if one of them achieved success. While Nizam al-Mulk and Hassan-i Sabbah sought high political office (Hassan eventually failed in his ambition to displace Nizam and later became a powerful sectarian leader), Khayyam reportedly requested only a place to live, pursue science, and pray, leading to him receiving an annual pension of 1200 mithqal of gold from the Nishapur treasury. However, the credibility of this anecdote is questioned by historians due to the significant age differences (about 30 years) between Khayyam and Nizam al-Mulk, making it unlikely for them to have been fellow students.

2.3. Career in the Seljuk Empire

In 1073-1074, following the conclusion of peace with Sultan Malik-Shah I, Khayyam entered Malik-Shah's service. He was invited by the Grand Vizier Nizam al-Mulk to meet Malik-Shah in Merv. Subsequently, Khayyam was commissioned to establish an observatory in Isfahan and lead a team of scientists in conducting precise astronomical observations. This endeavor aimed to revise the Persian calendar, a project that likely began with the observatory's opening in 1074 and concluded in 1079. During this period, Omar Khayyam and his colleagues meticulously measured the length of the year, reporting it as 365.24219858156 days. This measurement was extraordinarily accurate, especially considering that the length of the year changes in the sixth decimal place over a human lifetime. For comparison, the length of the year at the end of the 19th century was 365.242196 days, and today it is 365.242190 days.

2.4. Philosophical and Religious Inquiries

After the deaths of Malik-Shah and his vizier, Nizam al-Mulk (who was allegedly murdered by the Ismaili Order of Assassins), Khayyam lost his favored position at court. This led him to embark on a pilgrimage to Mecca. According to reports by Al-Qifti, a potential ulterior motive for this pilgrimage was to publicly demonstrate his faith, thus alleviating suspicions of skepticism and countering accusations of unorthodoxy (including possible sympathies with Zoroastrianism) leveled against him by a hostile clergy. Following his pilgrimage, Sultan Sanjar invited Khayyam to Merv, possibly to serve as a court astrologer. However, Khayyam apparently did not have a strong belief in astrology or divination, and one of his pupils, Nizami Aruzi, noted that he had not observed any great scientists of his time who held such beliefs. Khayyam's predictions regarding weather, a task sometimes assigned to court astrologers, were reportedly not always accurate. George Saliba clarifies that the Arabic term 'ilm al-nujūm^Arabic, often used in sources referring to Khayyam, can be misinterpreted as solely astrology; however, since at least the mid-10th century, this science was divided into two parts: one dealing with astrology and the other with theoretical mathematical astronomy.

Khayyam's philosophical and religious outlook has been a subject of extensive debate. He considered himself a student of Avicenna, and prior to his death, he was reportedly reading the metaphysics section of Avicenna's The Book of Healing. His philosophical papers explore concepts such as existence and its relation to universals (in On existence), and free will versus determinism (in The necessity of contradiction in the world, determinism and subsistence). He also authored treatises like On being and necessity, The Treatise on Transcendence in Existence, On the knowledge of the universal principles of existence, and Abridgement concerning natural phenomena. Khayyam himself lamented the decline of scientific inquiry in his era, stating: "We are the victims of an age when men of science are discredited, and only a few remain who are capable of engaging in scientific research. Our philosophers spend all their time in mixing true with false and are interested in nothing but outward show; such little learning as they have they extend on material ends. When they see a man sincere and unremitting in his search for the truth, one who will have nothing to do with falsehood and pretence, they mock and despise him." This quote reflects his critical view of the intellectual environment.

His quatrains are often interpreted as reflecting philosophical pessimism, nihilism, Epicureanism, fatalism, and agnosticism. This literal interpretation suggests he challenged the notion of divine intervention in every event and did not believe in a Judgment Day or post-mortem rewards and punishments, instead supporting the idea that natural laws explain all observed phenomena. Conversely, some scholars interpret his work as mystical Sufi poetry, viewing his references to wine and drunkenness as metaphors for divine rapture. However, many Iranian experts, including Mohammad Ali Foroughi, rejected the Sufi interpretation, arguing there is no formal evidence of his adherence to Sufism. Khayyam's prose works, written in the Peripatetic style, are explicitly theistic, engaging with subjects like the existence of God and theodicy, indicating a focus on metaphysics rather than Sufi subtleties. His biographers' accounts often conflict: those praising his religiosity tend to omit his poetry, while those mentioning his poetry rarely highlight his religious character. Ultimately, his religious views remain complex and open to interpretation, reflecting a deep engagement with the fundamental questions of existence and faith.

2.5. Later Life and Death

Khayyam was eventually permitted to return to Nishapur due to his declining health. Upon his return, he is said to have lived a reclusive life. Omar Khayyam died at the age of 83 in his hometown of Nishapur on December 4, 1131. He is buried in what is now the Mausoleum of Omar Khayyam.

2.6. Tomb

The Mausoleum of Omar Khayyam in Nishapur is a significant memorial to the polymath. One of his disciples, Nizami Aruzi, recounted a story that in 1112-1113, while in Balkh with Al-Isfizari (a collaborator on the Jalali calendar), Khayyam prophesied that his "tomb shall be in a spot where the north wind may scatter roses over it." Four years after Khayyam's death, Aruzi located his tomb in a cemetery within a large and well-known quarter of Nishapur, on the road to Merv. As Khayyam had foreseen, his tomb was situated at the foot of a garden wall, with pear and apricot trees extending their branches over it and dropping their flowers, thus concealing his tombstone. The architectural form of his mausoleum itself is designed to resemble a tent, a symbolic nod to his ancestral profession as a tent-maker. Some of his rubaiyats are inscribed on the exterior of the mausoleum in calligraphic (taliq script) decoration.

3.1. Geometric Algebra and Cubic Equations

Khayyam is considered a precursor to Descartes in the invention of analytic geometry due to his comprehensive geometric approach to algebraic equations. In his Treatise on the Division of a Quadrant of a Circle, he applied algebraic principles to geometry, investigating whether a circular quadrant could be divided into two parts such that line segments projected from the dividing point to the perpendicular diameters formed a specific ratio. His solutions involved curve constructions that led to equations with cubic and quadratic terms.

Khayyam was the first to conceptualize a general theory of cubic equations and the first to geometrically solve every type of cubic equation for positive roots. His Treatise on Algebra systematically addresses these equations, divided into three parts: those solvable with a compass and straightedge, those solvable using conic sections, and those involving the inverse of an unknown. He compiled an exhaustive list of all possible equations involving lines, squares, and cubes, considering three binomial, nine trinomial, and seven tetranomial equations. While he provided numerical solutions for first- and second-degree polynomials through geometric construction, he identified fourteen distinct types of cubics that could not be reduced to a lower degree. For these, he presented geometric solutions by leveraging the properties of conic sections, determining the positive root of a cubic equation as the abscissa of the intersection point of two conics (e.g., two parabolas, or a parabola and a circle). Khayyam explicitly recognized that the arithmetic problem of these cubics remained unsolved, expressing hope that "possibly someone else will come to know it after us." This challenge was finally met in the 16th century by Cardano, Del Ferro, and Tartaglia in Renaissance Italy. Khayyam's work essentially sought to unify algebra and geometry, a systematic and exact method praised for its "power of generalization and its rigorously systematic procedure" by mathematician Franz Woepcke. His methods were later extended to solving fourth-degree equations by M. Hachtroudi.

3.2. Theory of Parallels

A significant portion of Khayyam's Commentary on the Difficulties Concerning the Postulates of Euclid's Elements is dedicated to the parallel axiom. His treatise is recognized as the first treatment of the axiom not based on petitio principii (begging the question), but on a more intuitive postulate. Khayyam meticulously refuted previous attempts by other mathematicians to "prove" the parallel postulate, arguing that each had relied on assumptions no easier to admit than the Fifth Postulate itself. Drawing on Aristotle's perspectives, he rejected the use of movement in geometry, thereby dismissing attempts like that of Ibn al-Haytham. Dissatisfied with the inability of mathematicians to prove Euclid's statement from his other postulates, Khayyam attempted to connect the axiom with the Fourth Postulate, which asserts that all right angles are equal.

Khayyam was the first to systematically consider the three distinct cases of acute, obtuse, and right angles for the summit angles of a Khayyam-Saccheri quadrilateral. After proving several theorems about these cases, he demonstrated that Euclid's Postulate V (the parallel postulate) follows from the right angle hypothesis and rejected the obtuse and acute cases as self-contradictory. His elaborate efforts to prove the parallel postulate were crucial for the future development of geometry, as they clearly showed the possibility of non-Euclidean geometry. Today, the hypotheses of acute, obtuse, and right angles are known to correspond, respectively, to the non-Euclidean hyperbolic geometry of Gauss-Bolyai-Lobachevsky, Riemannian geometry, and Euclidean geometry.

Khayyam's work on parallels reached Europe through Tusi's commentaries. John Wallis, a geometry professor at Oxford University, translated Tusi's commentary into Latin. Later, the Jesuit geometer Girolamo Saccheri, whose 1733 work euclides ab omni naevo vindicatus is considered a precursor to non-Euclidean geometry, was familiar with Wallis's work. The American historian of mathematics David Eugene Smith noted that Saccheri utilized the same lemma as Tusi, even adopting identical figure lettering and purpose, and acknowledged that Tusi explicitly attributed this lemma to Omar Khayyam, suggesting Khayyam as the inspirer.

3.3. Real Number Concept

Khayyam's treatise on Euclid also includes a significant contribution to the theory of proportions and the compounding of ratios. He explored the intricate relationship between the concept of ratio and the concept of number, explicitly addressing various theoretical difficulties. Notably, he advanced the theoretical study of the irrational number. Dissatisfied with Euclid's definition of equal ratios, Khayyam redefined the concept of a number using a continued fraction as a means of expressing a ratio. Historians of mathematics, like Youschkevitch and Rosenfeld, argue that Khayyam "began a true revolution in the doctrine of number" by placing irrational quantities and numbers on the same operational scale. Similarly, Dirk Jan Struik observed that Omar was "on the road to that extension of the number concept which leads to the notion of the real number."

3.4. Binomial Theorem and Root Extraction

In his algebraic treatise, Omar Khayyam referred to a lost book he had written, likely titled Difficulties of Arithmetic (Mushkilāt al-Ḥisāb^Arabic). This book detailed the extraction of the $n$th root of natural numbers using a non-geometric law he had discovered. Based on this context, some historians of mathematics, including D. J. Struik, believe that Khayyam must have been aware of the formula for the expansion of the binomial $(a+b)^n$, where n is a positive integer. While the case for power 2 was explicitly stated in Euclid's Elements and for power 3 by Indian mathematicians, Khayyam is recognized as the mathematician who understood the importance of a general binomial theorem, a claim supported by his ability to extract roots.

Interestingly, one of Khayyam's predecessors, al-Karaji, had already identified the triangular arrangement of binomial expansion coefficients, later known to Europeans as Pascal's triangle. Khayyam further popularized this triangular array in Iran, leading to its local designation as Omar Khayyam's triangle.

4.1. Jalali Calendar Reform

In 1074-1075, Sultan Malik-Shah commissioned Omar Khayyam to establish an observatory in Isfahan and to reform the Persian calendar. Khayyam led a panel of eight scholars dedicated to conducting large-scale astronomical observations and revising existing astronomical tables. Their recalibration of the calendar precisely fixed the first day of the year at the exact moment the Sun's center crossed the vernal equinox. This marked the beginning of spring, known as Nowruz, the day when the Sun enters the first degree of Aries before noon.

The resulting calendar, named the Jalālī calendar in honor of Malik-Shah, was inaugurated on March 15, 1079. It was a true solar calendar, with the duration of each month corresponding to the time the Sun spent in its respective Zodiac sign. The calendar reform introduced a unique 33-year intercalation cycle. As documented by Khazini, Khayyam's team implemented a system of quadrennial and quinquennial leap years, resulting in 25 ordinary years of 365 days and 8 leap years of 366 days. The Jalālī calendar was remarkably accurate, accumulating an error of only one day over 5,000 years, making it more precise than the Gregorian calendar of 1582, which has an error of one day every 3,330 years. It remained in use across Greater Iran from the 11th to the 20th centuries and became the official national calendar of Qajar Iran in 1911. In 1925, it was simplified and modernized into the modern Iranian calendar. The German historian of mathematics Moritz Cantor considered it the most perfect calendar ever devised.

4.2. Astronomical Observations

Khayyam's precise calculations of the solar year were conducted at the Isfahan observatory. While working on the calendar, he and his team made extensive observations that allowed for their highly accurate determination of the year's length. Though a star map he reportedly created has since been lost, his work at the observatory, alongside his colleagues, demonstrated his profound understanding and practical application of astronomical principles.

Despite his work in astronomy, Khayyam reportedly held no strong belief in astrology or divination. His student, Nizami Aruzi of Samarcand, stated, "I did not observe that he (Omar Khayyam) had any great belief in astrological predictions, nor have I seen or heard of any of the great [scientists] who held such beliefs." While he did serve Sultan Sanjar as a court astrologer at one point, his performance in predicting weather was apparently not impressive. The Arabic term 'ilm al-nujūm^Arabic, often associated with his work, encompassed both astrology and theoretical mathematical astronomy, but Khayyam's focus was clearly on the latter. He is also credited with demonstrating that the universe does not revolve around the Earth, as was commonly believed, and that stars are fixed objects in space, insights that were ahead of his time and later adopted by Christian astronomers.

5.1. The Rubaiyat

The earliest mention of Omar Khayyam's poetry comes from the historian Imad al-Din al-Isfahani, a younger contemporary, who explicitly identified him as both a poet and a scientist in his 1174 work Kharidat al-qasr. Early examples of his Rubaiyat appear in theological and historical texts from the 13th century, such as those by Fakhr al-Din Razi, Daya, and Juvayni. By 1340, Jajarmi included thirteen of Khayyam's quatrains in his anthology Mu'nis al-ahrār. A relatively late but significant manuscript, the Bodleian Library MS. Ouseley 140, written in Shiraz in 1460, contains 158 quatrains. Additionally, 25 Arabic poems are attributed to him by various historians.

The term Rubaiyat is the plural of the Persian word rubāʿī, meaning "quatrain" or "four-line verse," considered the oldest indigenous poetic form in Persian literature since the mid-9th century. Rooted in Arabic metrics, the rubāʿī rhyme scheme typically involves the first, second, and fourth half-lines rhyming, though sometimes all four do. This concise form allows poets to express fleeting thoughts and intense poetic experiences with immediacy, prioritizing poetic notion over strict formal constraints. Khayyam's Rubaiyat is widely regarded as the pinnacle of this art form.

Despite this, the authenticity of many poems attributed to Khayyam has been a long-standing debate among scholars. Skeptics, like Hans Heinrich Schaeder in 1934, even suggested that Khayyam's name should be "struck out from the history of Persian literature" due to a lack of confidently attributable material. While some early verses are confirmed to have been in circulation shortly after his death, it does not definitively prove his authorship. Edward Granville Browne noted the difficulty of distinguishing authentic from spurious quatrains, stating that while Khayyam certainly wrote many, it is " hardly possible, save in a few exceptional cases, to assert positively that he wrote any of those ascribed to him." It is believed that Khayyam's poetry may have served as a leisure pursuit for scholars and scientists, composed to edify or entertain their inner circles.

Khayyam's posthumous popular fame largely stems from the immense success of Edward FitzGerald's 1859 translation, Rubaiyat of Omar Khayyam. FitzGerald, a scholar of independent means, lived a reclusive life, dedicating himself to reading and translation. His friendship with Edward Cowell, who introduced him to Persian literature and a manuscript of Khayyam's quatrains (the 'Ouseley manuscript' from the Bodleian Library), was a pivotal moment. FitzGerald, identifying with Khayyam's skeptical and hedonistic undertones, loosely translated the quatrains, creating a work that initially struggled but gained widespread popularity, especially among the Pre-Raphaelites and in the fin de siècle period. By 1929, over 300 editions of FitzGerald's translation had been published, and many more followed, cementing Khayyam's global reputation as a poet.

5.2. Philosophical Thought

Omar Khayyam explicitly considered himself an intellectual disciple of Avicenna, often citing Avicenna's The Book of Healing for its metaphysical insights. Six philosophical treatises are attributed to Khayyam, showcasing the breadth of his thought:

• On Existence (Fi'l-wujūd^Arabic), written in Persian, explores the nature of existence and its relation to universals.
• The Necessity of Contradiction in the World, Determinism and Subsistence (Darurat al-tadād fi'l-'ālam wa'l-jabr wa'l-baqā'^Arabic), in Arabic, delves into the complex interplay between free will and determinism.
• Other works include On Being and Necessity (Risālah fī'l-kawn wa'l-taklīf^Arabic), The Treatise on Transcendence in Existence (al-Risālah al-ulā fi'l-wujūd^Arabic), On the Knowledge of the Universal Principles of Existence (Risālah dar 'ilm kulliyāt-i wujūd^Arabic), and Abridgement Concerning Natural Phenomena (Mukhtasar fi'l-Tabi'iyyāt^Arabic).

Khayyam's philosophical outlook is often characterized by a profound skepticism and a deep sense of nihilism and fatalism. He articulated his frustration with the intellectual climate of his time, lamenting the marginalization of genuine scientific inquiry:
"We are the victims of an age when men of science are discredited, and only a few remain who are capable of engaging in scientific research. Our philosophers spend all their time in mixing true with false and are interested in nothing but outward show; such little learning as they have they extend on material ends. When they see a man sincere and unremitting in his search for the truth, one who will have nothing to do with falsehood and pretence, they mock and despise him."
This quote highlights his critical stance against what he perceived as intellectual stagnation and superficiality among his contemporaries. His philosophical journey appears to have led him to a fundamental skepticism about the limits of human understanding, particularly regarding the creator's intentions, often expressed as "No one speaks the truth, from where one comes and where one goes," or "No one knows the Creator's intentions." This deep despair over philosophical limitations and religious oppression led him to conclude that "everything is fleeting, ephemeral, and precarious," a sentiment often echoed in his poetry.

5.3. Religious Views

Omar Khayyam's religious views remain a subject of intense academic debate, with interpretations ranging from radical skepticism to profound Sufi mysticism. A literal reading of many of his quatrains suggests a philosophical stance that combines philosophical pessimism, nihilism, Epicureanism, fatalism, and agnosticism. This interpretation is supported by prominent Iranologists like Arthur Christensen and Sadegh Hedayat, with Hedayat even asserting that Khayyam was an atheist, a materialist, and a pessimist who looked at religious questions with skepticism and "hated the fanaticism, narrow-mindedness, and the spirit of vengeance of the mullas." Khayyam's Arabic poems also express a pessimistic viewpoint consistent with a rationalist philosopher. Edward FitzGerald's translation emphasized the religious skepticism, claiming Khayyam "was hated and dreaded by the Sufis" and denying any divine allegory in his work, famously stating his "Wine is the veritable Juice of the Grape." Khayyam's verses have been cited in the context of New Atheism, notably by Christopher Hitchens.

Historical accounts further complicate this picture. Al-Qifti, a 13th-century historian, reported that Khayyam's poems were only outwardly Sufi in style but concealed an anti-religious agenda. He also noted that Khayyam was once indicted for impiety and undertook a pilgrimage to Mecca as a public demonstration of his piety, later returning to Nishapur to practice a strictly religious life, concealing his true convictions. Khayyam's own verses, as found in some attributions, overtly question orthodox Islamic tenets:
"The Koran! well, come put me to the test,
Lovely old book in hideous error drest,
Believe me, I can quote the Koran too,
The unbeliever knows his Koran best.
And do you think that unto such as you,
A maggot-minded, starved, fanatic crew,
God gave the Secret, and denied it me?
Well, well, what matters it! believe that too."
Other quatrains express a similar skeptical outlook on divine answers and the afterlife:
"Look not above, there is no answer there;
Pray not, for no one listens to your prayer;
Near is as near to God as any Far,
And Here is just the same deceit as There."
"Men talk of heaven,-there is no heaven but here;
Men talk of hell,-there is no hell but here;
Men of hereafters talk, and future lives,
O love, there is no other life-but here."
A 13th-century account describes him as "versed in all the wisdom of the Greeks," and as undevout, with his astronomy likely contributing to this. It states he adhered to no religious sect, and that agnosticism, not faith, was the keynote of his works.

Conversely, some commentators argue that Khayyam's poetry, particularly its references to wine and intoxication, should be understood metaphorically within the Sufi tradition, representing divine rapture or an enlightened state (baqaa). Scholars like J. B. Nicolas and Idries Shah have defended Khayyam as a Sufi mystic, attributing literal interpretations to the shortcomings of FitzGerald's translation. Indeed, in his prose work On the Knowledge of the Principles of Existence, Khayyam appears to endorse the Sufi path, and some suggest he saw Sufism as an ally against orthodox religiosity.

However, many prominent Iranian scholars, including Mohammad Ali Foroughi and Mojtaba Minovi, have rejected the Sufi hypothesis, asserting no evidence of his formal adherence. They argue that Sufi interpretations often require stretching the content of his Rubāʿīyyāt to fit classical Sufi doctrine. Furthermore, Khayyam was intensely disliked by several celebrated Sufi mystics of his century, such as Shams Tabrizi, Najm al-Din Daya (who called him "an unhappy philosopher, atheist, and materialist"), and Attar (who viewed him as a free-thinking scientist awaiting punishment).

Seyyed Hossein Nasr argues that a literal interpretation of Khayyam's verses, many of which are of uncertain authenticity, is "reductive." He points to Khayyam's interpretive translation of Avicenna's treatise Discourse on Unity, where he expresses orthodox views on Divine Unity. His known prose works, written in a Peripatetic style, are explicitly theistic, engaging with themes like the existence of God and theodicy, suggesting his involvement in metaphysical problems rather than Sufism. Aminrazavi notes that Khayyam's treatises include salutations and prayers, praising God and Muhammad, and that he is often referred to with religious honorifics like Imam, The Patron of Faith (Ghīyāth al-Dīn^Arabic), and The Evidence of Truth (Hujjat al-Haqq^Arabic). Yet, Aminrazavi also observes that biographers who praise his religiosity generally avoid his poetry, while those who mention his poetry often do not praise his religious character. Al-Bayhaqi, an early biographer, portrays Omar as a pious man who held orthodox views until his final moments.

Based on all available evidence, Khayyam's religious identity remains complex and debated, leading to sharply conflicting appreciations and criticisms throughout history.

7.1. Contemporary Recognition

During his own lifetime, Omar Khayyam was highly esteemed, particularly for his scientific acumen. Various biographical accounts describe him as unparalleled in scientific knowledge and achievement, often referring to him by epithets such as King of the Wise (ملك الحکماء_{Malik al-Ḥukamā}^Arabic). Shahrazuri (d. 1300), a mathematician himself, held Khayyam in high regard, claiming he could be considered "the successor of Avicenna in the various branches of philosophic learning." Similarly, Al-Qifti (d. 1248), despite his disagreements with Khayyam's philosophical views, conceded that he was "unrivalled in his knowledge of natural philosophy and astronomy." However, while celebrated for his scientific prowess, Khayyam's status as a poet of the first rank was a relatively late development, according to scholars like John Andrew Boyle.

7.2. Western Reception and Influence

The first European to draw attention to Omar Khayyam was Thomas Hyde, who translated one of his quatrains into Latin in 1700 as part of his work Historia religionis veterum Persarum eorumque magorum. Western interest in Persia grew significantly with the Orientalism movement of the 19th century. Early translations included those by Joseph von Hammer-Purgstall (German, 1818) and Gore Ouseley (English, 1846), but Khayyam remained relatively obscure in the West until the publication of Edward FitzGerald's Rubaiyat of Omar Khayyam in 1859.

FitzGerald's translation was initially unsuccessful but gained popularity after 1861 through the efforts of Whitley Stokes and was greatly admired by the Pre-Raphaelites. A third edition printed in 1872 further fueled interest in America. By the 1880s, the Rubaiyat had become immensely popular across the English-speaking world, leading to the formation of numerous "Omar Khayyam Clubs" and a pervasive "fin de siècle cult of the Rubaiyat." Khayyam's poems have since been translated into many languages, with later translations often being more literal than FitzGerald's.

7.3. Cultural Impact and Memorials

FitzGerald's translation also had a significant effect in Iran, rekindling domestic interest in Khayyam as a poet. Sadegh Hedayat contributed to this resurgence with his 1934 work Songs of Khayyam (Taranehha-ye Khayyam), reintroducing Khayyam's poetic legacy to modern Iran.

Modern commemorations and tributes to Omar Khayyam are widespread:

• Under the Pahlavi dynasty, a new monument of white marble, designed by architect Houshang Seyhoun, was erected over his tomb in Nishapur.
• A statue by Abolhassan Sadighi was installed in Laleh Park, Tehran, in the 1960s, with a bust by the same sculptor placed near Khayyam's mausoleum in Nishapur.
• In 2009, Iran donated a pavilion featuring statues of Khayyam and other Persian scholars to the United Nations Office in Vienna, inaugurated at the Vienna International Centre.
• In 2016, three new statues of Khayyam were unveiled: one at the University of Oklahoma, one in Nishapur, and another in Florence, Italy.
• Over 150 composers, beginning with Liza Lehmann, have drawn inspiration from the Rubaiyat for their musical works.

The anglicized name "Omar the Tentmaker," derived from FitzGerald's translation, resonated in English-speaking popular culture for a time. This led to literary works such as Nathan Haskell Dole's 1898 novel Omar, the Tentmaker: A Romance of Old Persia and John Smith Clarke's 1910 historical novel Omar the Tentmaker of Naishapur. "Omar the Tentmaker" was also the title of a 1914 play by Richard Walton Tully, later adapted into a silent film in 1922. Notably, US General Omar Bradley was nicknamed "Omar the Tent-Maker" during World War II.

Khayyam's diverse talents and intellectual pursuits also captivated many writers in the Ottoman Empire and modern Turkey. Scholars often found in Khayyam a means to enhance their own poetic and intellectual standing. For many Muslim reformers, his verses provided a counterpoint to conservative norms, offering space for independent thought and a more liberal lifestyle. Figures like Abdullah Cevdet, Rıza Tevfik, and Yahya Kemal used Khayyam's themes to justify progressive ideologies and celebrate liberal aspects of their lives, presenting him as a cultural, political, and intellectual role model who reconciled Islam with modern conventions. Similarly, Turkish leftist poets and intellectuals, including Nâzım Hikmet, imbued his voice with humanistic tones in the vernacular to champion their socialist worldviews. Khayyam's resurgence in spoken Turkish since the 1980s has transformed him into a "poet of the people," with numerous books and translations revitalizing his historical significance. Conversely, scholars like Dāniş, Tevfik, and Gölpınarlı advocated for rigorous source criticism to discern the genuine Khayyam amidst historical perceptions of his sociocultural image.

The lunar crater Omar Khayyam was named in his honor in 1970, and the minor planet 3095 Omarkhayyam was discovered by Soviet astronomer Lyudmila Zhuravlyova in 1980. Google has also commemorated him with two Google Doodles on his birthday, on May 18, 2012, and May 18, 2019.

7.3.1. The Moving Finger quatrain

One of the most popular quatrains in the Anglosphere attributed to Omar Khayyam is "The Moving Finger," from Edward FitzGerald's translation of the Rubaiyat. It reads:
"The Moving Finger writes; and having writ,
Moves on: nor all your Piety nor Wit
Shall lure it back to cancel half a Line,
Nor all your Tears wash out a Word of it."
This quatrain has inspired various cultural works, including Agatha Christie's 1942 novel The Moving Finger. It has also been quoted by prominent figures, such as Martin Luther King Jr. in his speech "Beyond Vietnam: A Time to Break Silence":
"We may cry out desperately for time to pause in her passage, but time is adamant to every plea and rushes on. Over the bleached bones and jumbled residues of numerous civilizations are written the pathetic words, 'Too late.' There is an invisible book of life that faithfully records our vigilance or our neglect. Omar Khayyam is right: 'The moving finger writes, and having writ moves on.'"
Former US President Bill Clinton also cited this quatrain in an apologetic speech regarding the Clinton-Lewinsky scandal.