New research suggests that Nicolaus Copernicus’s heliocentric model of the solar system may have been significantly influenced by the work of a 14th-century Muslim astronomer, Ibn al-Shatir. The study draws detailed comparisons between the planetary models of both figures and proposes that Copernicus’s ideas could have stemmed—directly or indirectly—from earlier Islamic scientific traditions.
Copernicus, the renowned 16th-century Polish astronomer, is widely credited with initiating the so-called Copernican Revolution by proposing that the Sun, not the Earth, lay at the centre of the universe. His work challenged the prevailing geocentric models derived from Aristotle and Ptolemy and helped lay the foundation for modern astronomy.
But according to a recently completed PhD thesis by Dr. Salama Al-Mansouri of the University of Sharjah, Copernicus’s model bears a remarkable resemblance to one developed nearly 200 years earlier by Ibn al-Shatir, a Damascene astronomer who served as the timekeeper of the Umayyad Mosque.
“Ibn al-Shatir was the first astronomer to have successfully challenged the Ptolemaic cosmological system of planets revolving around Earth and corrected the theory’s inaccuracies about two centuries before Copernicus,” says Dr. Al-Mansouri. Her study, now available through the Sharjah University Library, offers a critical textual analysis of the two astronomers’ work, focusing in particular on Copernicus’s De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) and Ibn al-Shatir’s treatise Nihāyat al-Sul fī Taṣḥīḥ al-Uṣūl (The Final Quest Concerning the Rectification of Principles).
A manuscript of Ibn al-Shatir (in Arabic) with tables showing movements of starts per years, months and days. Image courtesy The Leiden University Libraries.
The research reveals “compelling correlations,” especially in the mathematical models used to represent planetary motion. According to the study, “Ibn al-Shatir’s astronomical manuscripts, particularly his work in Nihāyat al-Sul, demonstrate planetary models that predate and closely mirror those later proposed by Copernicus, indicating a shared mathematical lineage,” says Mesut Idriz, professor of history and Islamic civilization at the University of Sharjah and one of the study’s supervisors.
Among the most notable parallels are their respective models for the Moon and Mercury. The study notes that both Ibn al-Shatir and Copernicus corrected Ptolemy’s exaggerated lunar distance variations using similar epicyclic geometries. “This is nearly identical to Copernicus’s lunar model in De Revolutionibus,” the research states. “Both reduced the lunar distance fluctuation from Ptolemy’s factor of two to a more accurate range, relying on similar geometric constructions.”
Kitab al-tafhom li-awaill sinaat al-tanjim or Comprehensive introduction to the principles of astrology, a question-and-answer format about astrologer: geometry, arithmetic, and number theory, by the famous Islamic astronomer Biruni. Credit: Or 8349. Public domain, Qatar Digital Library
For the inner planets, Copernicus employed secondary epicycles and a device resembling the Tusi-couple—a mathematical tool named after the 13th-century Persian polymath Nasir al-Din al-Tusi. Ibn al-Shatir had used a similar mechanism to eliminate the equant, a problematic element in Ptolemaic astronomy. The study argues that Copernicus’s use of comparable constructions suggests that he may have adopted Ibn al-Shatir’s techniques and adapted them within a heliocentric framework.
Even Copernicus’s solar model closely mirrors Ibn al-Shatir’s approach. “Ibn al-Shatir’s solar model, with a new eccentricity and epicycles yielding a maximum solar equation of 2;2,6°, parallels Copernicus’s solar calculations,” the study says. “This suggests Copernicus may have adopted Ibn al-Shatir’s numerical tables or methods, adapting them to his Sun-centered system.”
Despite these similarities, the study acknowledges that Ibn al-Shatir remained within a geocentric paradigm. However, Dr. Al-Mansouri argues that the precision of his refinements made them readily compatible with Copernicus’s heliocentric reinterpretation. “Our analysis reveals that Ibn al-Shatir’s treatise, though geocentric in intent, produced results so aligned with heliocentrism that Copernicus’s debt to him is undeniable—two centuries of separation could not erase this intellectual kinship.”
But how might Copernicus have encountered these ideas? Dr. Al-Mansouri surveyed Arabic manuscripts and their Latin translations preserved in European archives—including those in Kraków and the Vatican—where Copernicus studied and developed his astronomical theories. She reports that Nihāyat al-Sul was among the materials archived there in its original Arabic. “Though in its original Arabic version, the manuscript could not have escaped the attention of a scholar like Copernicus,” she writes.
No Latin translation of Ibn al-Shatir’s writings is known to have existed at the time, which means direct influence cannot be proven. However, the study suggests that the Polish astronomer likely accessed these ideas through “intermediary channels”—possibly through scholars who had translated or transmitted parts of the work indirectly.
Astrophysicist Mashhoor Al-Wardat underscores the implications of these findings:
The striking similarity between the planetary models developed by Ibn al-Shatir and Copernicus, particularly those concerning the orbits of Mercury and the Moon, provides clear evidence of Copernicus’s reliance on Ibn al-Shatir’s work …This raises profound questions about the transmission of knowledge from Islamic civilization to Europe and about the roots of modern astronomy.
Interpreting historical astronomical manuscripts is no simple task. Professor Idriz notes that studies like this one require a “unique intersection of expertise—astronomy, manuscript studies, and historiography.” Dr. Al-Mansouri relied on support from the Sharjah Academy for Astronomy, Space Sciences and Technology, which has become a regional hub for Arabic and Islamic science research.
Prof. Hamid al-Naimiy, a renowned astronomer and Chancellor of the University of Sharjah, served as the study’s main supervisor. “This study is a clarion call to rewrite the history of astronomy,” he says, “ensuring that the brilliance of Muslim scholars like Ibn al-Shatir stands alongside Copernicus in our collective narrative of scientific progress.”
Al-Naimiy describes Ibn al-Shatir’s model as “dismantling the Ptolemaic system and correcting its flaws two centuries before Copernicus.” He adds, “This work emphasizes the significant contributions of our heritage to global astronomy.”
Dr. Al-Mansouri sees broader implications. The study highlights how contributions from non-Western scholars are often marginalized in narratives of scientific progress. “Ibn al-Shatir’s empirical refinements within a geocentric framework, paralleled by Copernicus’s adaptation, illustrate how incremental improvements can precede paradigm shifts,” she says. “This research offers a model for modern science, where foundational work in one context can catalyze breakthroughs in another.”
The findings invite historians to reconsider the linear, Eurocentric story of the Scientific Revolution. By drawing attention to the shared mathematical techniques and overlapping astronomical models, the study urges greater acknowledgment of the Islamic Golden Age’s role in laying the groundwork for Renaissance astronomy—and calls for updates to science curricula to reflect a more inclusive and accurate account of intellectual history.
New research suggests that Nicolaus Copernicus’s heliocentric model of the solar system may have been significantly influenced by the work of a 14th-century Muslim astronomer, Ibn al-Shatir. The study draws detailed comparisons between the planetary models of both figures and proposes that Copernicus’s ideas could have stemmed—directly or indirectly—from earlier Islamic scientific traditions.
Copernicus, the renowned 16th-century Polish astronomer, is widely credited with initiating the so-called Copernican Revolution by proposing that the Sun, not the Earth, lay at the centre of the universe. His work challenged the prevailing geocentric models derived from Aristotle and Ptolemy and helped lay the foundation for modern astronomy.
But according to a recently completed PhD thesis by Dr. Salama Al-Mansouri of the University of Sharjah, Copernicus’s model bears a remarkable resemblance to one developed nearly 200 years earlier by Ibn al-Shatir, a Damascene astronomer who served as the timekeeper of the Umayyad Mosque.
“Ibn al-Shatir was the first astronomer to have successfully challenged the Ptolemaic cosmological system of planets revolving around Earth and corrected the theory’s inaccuracies about two centuries before Copernicus,” says Dr. Al-Mansouri. Her study, now available through the Sharjah University Library, offers a critical textual analysis of the two astronomers’ work, focusing in particular on Copernicus’s De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) and Ibn al-Shatir’s treatise Nihāyat al-Sul fī Taṣḥīḥ al-Uṣūl (The Final Quest Concerning the Rectification of Principles).
The research reveals “compelling correlations,” especially in the mathematical models used to represent planetary motion. According to the study, “Ibn al-Shatir’s astronomical manuscripts, particularly his work in Nihāyat al-Sul, demonstrate planetary models that predate and closely mirror those later proposed by Copernicus, indicating a shared mathematical lineage,” says Mesut Idriz, professor of history and Islamic civilization at the University of Sharjah and one of the study’s supervisors.
Among the most notable parallels are their respective models for the Moon and Mercury. The study notes that both Ibn al-Shatir and Copernicus corrected Ptolemy’s exaggerated lunar distance variations using similar epicyclic geometries. “This is nearly identical to Copernicus’s lunar model in De Revolutionibus,” the research states. “Both reduced the lunar distance fluctuation from Ptolemy’s factor of two to a more accurate range, relying on similar geometric constructions.”
For the inner planets, Copernicus employed secondary epicycles and a device resembling the Tusi-couple—a mathematical tool named after the 13th-century Persian polymath Nasir al-Din al-Tusi. Ibn al-Shatir had used a similar mechanism to eliminate the equant, a problematic element in Ptolemaic astronomy. The study argues that Copernicus’s use of comparable constructions suggests that he may have adopted Ibn al-Shatir’s techniques and adapted them within a heliocentric framework.
Even Copernicus’s solar model closely mirrors Ibn al-Shatir’s approach. “Ibn al-Shatir’s solar model, with a new eccentricity and epicycles yielding a maximum solar equation of 2;2,6°, parallels Copernicus’s solar calculations,” the study says. “This suggests Copernicus may have adopted Ibn al-Shatir’s numerical tables or methods, adapting them to his Sun-centered system.”
Despite these similarities, the study acknowledges that Ibn al-Shatir remained within a geocentric paradigm. However, Dr. Al-Mansouri argues that the precision of his refinements made them readily compatible with Copernicus’s heliocentric reinterpretation. “Our analysis reveals that Ibn al-Shatir’s treatise, though geocentric in intent, produced results so aligned with heliocentrism that Copernicus’s debt to him is undeniable—two centuries of separation could not erase this intellectual kinship.”
But how might Copernicus have encountered these ideas? Dr. Al-Mansouri surveyed Arabic manuscripts and their Latin translations preserved in European archives—including those in Kraków and the Vatican—where Copernicus studied and developed his astronomical theories. She reports that Nihāyat al-Sul was among the materials archived there in its original Arabic. “Though in its original Arabic version, the manuscript could not have escaped the attention of a scholar like Copernicus,” she writes.
No Latin translation of Ibn al-Shatir’s writings is known to have existed at the time, which means direct influence cannot be proven. However, the study suggests that the Polish astronomer likely accessed these ideas through “intermediary channels”—possibly through scholars who had translated or transmitted parts of the work indirectly.
Astrophysicist Mashhoor Al-Wardat underscores the implications of these findings:
The striking similarity between the planetary models developed by Ibn al-Shatir and Copernicus, particularly those concerning the orbits of Mercury and the Moon, provides clear evidence of Copernicus’s reliance on Ibn al-Shatir’s work …This raises profound questions about the transmission of knowledge from Islamic civilization to Europe and about the roots of modern astronomy.
Interpreting historical astronomical manuscripts is no simple task. Professor Idriz notes that studies like this one require a “unique intersection of expertise—astronomy, manuscript studies, and historiography.” Dr. Al-Mansouri relied on support from the Sharjah Academy for Astronomy, Space Sciences and Technology, which has become a regional hub for Arabic and Islamic science research.
Prof. Hamid al-Naimiy, a renowned astronomer and Chancellor of the University of Sharjah, served as the study’s main supervisor. “This study is a clarion call to rewrite the history of astronomy,” he says, “ensuring that the brilliance of Muslim scholars like Ibn al-Shatir stands alongside Copernicus in our collective narrative of scientific progress.”
Al-Naimiy describes Ibn al-Shatir’s model as “dismantling the Ptolemaic system and correcting its flaws two centuries before Copernicus.” He adds, “This work emphasizes the significant contributions of our heritage to global astronomy.”
Dr. Al-Mansouri sees broader implications. The study highlights how contributions from non-Western scholars are often marginalized in narratives of scientific progress. “Ibn al-Shatir’s empirical refinements within a geocentric framework, paralleled by Copernicus’s adaptation, illustrate how incremental improvements can precede paradigm shifts,” she says. “This research offers a model for modern science, where foundational work in one context can catalyze breakthroughs in another.”
The findings invite historians to reconsider the linear, Eurocentric story of the Scientific Revolution. By drawing attention to the shared mathematical techniques and overlapping astronomical models, the study urges greater acknowledgment of the Islamic Golden Age’s role in laying the groundwork for Renaissance astronomy—and calls for updates to science curricula to reflect a more inclusive and accurate account of intellectual history.
Click here to read the thesis, The Latest on the heliocentric theory as explained by Ibn al-Shater and Copernicus : a comparative analytical study
Top Image: Ibn-al-shatir’s lunar model from which Copernicus is reported to have borrowed in composing his cosmological model.
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