Scientific activity in medieval Europe was maintained by the activity of a number of significant scholars, active in a wide range of scientific disciplines and working in Greek, Latin, and Arabic-speaking cultures. This list provides a brief summary of their work.

Early Middle Ages

Anatolius of Laodicea (early 3rd century – 283), a bishop of Laodicea, one of the foremost scholars of his day in the physical sciences.

Nemesius (?-c. 390), a bishop of Emesa whose De Natura Hominis blended theology with Galenic medicine and is notable for his ideas concerning the brain. He also may have anticipated the discovery of the circulatory system.George Ripley And Charles A. Dana. Nemesius- Bishop Of Emesa IN "The American Cyclopaedia". George Jackson Fisher A Brief Historical Sketch of Discovery of the Circulation of the Blood IN Popular Science Monthly Volume 11, July 1877.

HERMANN PETERS and WILLIAM NETTER (1899) Pictorial history of ancient pharmacy - Chapter II - Pharmacy in the Middle Ages. Page 21 Quotation: Nemesius, in his work " De Natura Hominis" (300 A.D.), gives a theory of the circulation of the blood, which, imperfect though it be, is a step forward in the direction of the modern doctrine.

Isidore of Miletus (ca. 442 – ca. 537) was a renowned Byzantine scientist and mathematician. He was one of the two main Byzantine Greek architects (Anthemius of Tralles was the other) that Emperor Justinian I commissioned to design the cathedral Hagia Sophia in Constantinople from 532 to 537. He taught stereometry and physics at the universities, first of Alexandria then of Constantinople, and wrote a commentary on an older treatise on vaulting. Isidore is also renowned for producing the first comprehensive compilation of Archimedes' work, the Archimedes palimpsest.

Anthemius of Tralles (ca. 474 – ca. 534), a Byzantine professor of geometry and architecture, authored many influential works on mathematics and was one of the architects of the famed Hagia Sophia, the largest building in the world at its time. His works were among the most important source texts in the Arab world and Western Europe for centuries after.

John Philoponus (ca. 490–ca. 570), also known as John the Grammarian, a Christian Byzantine philosopher, launched a revolution in the understanding of physics by critiquing and correcting the earlier works of Aristotle. In the process he proposed important concepts such as a rudimentary notion of inertia and the invariant acceleration of falling objects. Although his works were repressed at various times in the Byzantine Empire, because of religious controversy, they would nevertheless become important to the understanding of physics throughout Europe and the Arab world.

Paul of Aegina (ca. 625–ca. 690), considered by some to be the greatest Christian Byzantine surgeon, developed many novel surgical techniques and authored the medical encyclopedia Medical Compendium in Seven Books. The book on surgery in particular was the definitive treatise in Europe and the Islamic world for hundreds of years.

The Venerable Bede (ca. 672–735), a Christian monk of the monasteries of Wearmouth and Jarrow who wrote a work On the Nature of Things, several books on the mathematical / astronomical subject of computus, the most influential entitled On the Reckoning of Time. He made original discoveries concerning the nature of the tides and his works on computus became required elements of the training of clergy, and thus greatly influenced early medieval knowledge of the natural world.

Rabanus Maurus (c. 780 – 856), a Christian monk and teacher, later archbishop of Mainz, who wrote a treatise on Computus and the encyclopedic work De universo. His teaching earned him the accolade of "Praeceptor Germaniae," or "the teacher of Germany."

Leo the Mathematician (c. 790 – after 869) was a Byzantine philosopher and logician associated with the Macedonian Renaissance. He wrote book-length works, poems, and many epigrams, and was also a compiler, who brought together a wide range of philosophical, medical, and astronomic texts. He composed his own medical encyclopaedia. He was archbishop of Thessalonica and later became the head of the Magnaura School of philosophy in Constantinople, where he taught Aristotelian logic.

Abbas Ibn Firnas (810 – 887), a polymath and inventor in Al-Andalus, made contributions in a variety of fields and is most known for his contributions to glass-making and aviation. He developed novel ways of manufacturing and using glass. A 17th century account states he broke his back at an unsuccessful attempt at flying in 875.

Al-Zahrawi (936-1013), a physician and scientist from Cordoba widely considered the father of modern surgery. He authored Al-Tasrif, a massive medical encyclopedia that detailed over 200 innovative surgical instruments and procedures. His books remained the definitive surgical textbooks in Europe for centuries.

Pope Sylvester II (c. 946–1003), a Christian scholar, teacher, mathematician, and later pope, reintroduced the abacus and armillary sphere to Western Europe after they had been lost for centuries following the Greco-Roman era. He was also responsible in part for the spread of the Hindu–Arabic numeral system in Western Europe.

Maslamah al-Majriti (died 1008), a mathematician, astronomer, and chemist in Al-Andalus, made contributions in many areas, from new techniques for surveying to updating and improving the astronomical tables of al-KhwarizmiSarton confirmed that al-Majriti corrected al-Khwarizmi's astronomical tables: and inventing a process for producing mercury oxide.The production of mercuric oxide was described in the Rutbat al-hakim ("The Sage's Step" or "The Rank of the Wise"), which is (dubiously) attributed to al-Majriti: He is most famous, though, for having helped transmit knowledge of mathematics and astronomy to Muslim Spain and Christian Western Europe.

Abulcasis (936-1013), a physician and scientist in Al-Andalus, is considered to be the father of modern surgery. He wrote numerous medical texts, developed many innovative surgical instruments, and developed a variety of new surgical techniques and practices. His texts were considered the definitive works on surgery in Europe until the Renaissance.

Eilmer of Malmesbury(b c.980), an English Benedictine monk who pioneered early aerodynamics. Around 1005, he launched a crude glider from a monastery tower, successfully traveling 200 meters before crashing, marking one of Europe's earliest documented aviation attempts.

High Middle Ages

Michael Psellos (ca. 1017-1078), was a Byzantine philosopher, politician and historian. He combined Platonic philosophy with Christian doctrine and initiated a renewal of Byzantine classical learning that later influenced the Italian Renaissance. He also made contributions to Byzantine culture, such of a reform of the university curriculum to emphasize the Greek classics, like the Homeric literature that, with Platonist thought, he understood as precursory to Christian revelation. He composed various treatises and poetry, on themes in theology, philosophy, grammar, law, medicine, mathematics, and the natural sciences.

Constantine the African (c. 1020–1087), a Christian native of Carthage, is best known for his translating of ancient Greek and Roman medical texts from Arabic into Latin while working at the Schola Medica Salernitana in Salerno, Italy. Among the works he translated were those of Hippocrates and Galen.

Trota of Salerno (Died c.1097), a pioneering Italian physician and medical writer associated with the School of Salerno. She authored foundational texts on women's medicine, gynaecology, and dermatology.

Arzachel (1029–1100), the foremost astronomer of the early second millennium, lived in Al-Andalus and greatly expanded the understanding and accuracy of planetary models and terrestrial measurements used for navigation. He developed key technologies including the equatorium and universal latitude-independent astrolabe.

Avempace (died 1138), a famous physicist from Al-Andalus who had an important influence on later physicists such as Galileo.Ernest A. Moody (June 1951). "Galileo and Avempace: The Dynamics of the Leaning Tower Experiment (II)", Journal of the History of Ideas 12 (3), p. 375–422 . He was the first to theorize the concept of a reaction force for every force exerted.Shlomo Pines (1964), "La dynamique d'Ibn Bajja", in Mélanges Alexandre Koyré, I, 442–468 [462, 468], Paris

Adelard of Bath (c. 1080 – c. 1152) was a 12th-century English scholar, known for his work in astronomy, astrology, philosophy and mathematics.

Avenzoar (1091–1161), from Al-Andalus, introduced an experimental method in surgery, employing animal testing in order to experiment with surgical procedures before applying them to human patients.Rabie E. Abdel-Halim (2005), "Contributions of Ibn Zuhr (Avenzoar) to the progress of surgery: A study and translations from his book Al-Taisir", Saudi Medical Journal 2005; Vol. 26 (9): 1333–1339. He also performed the earliest dissections and postmortem autopsies on both humans as well as animals.Islamic medicine, Hutchinson Encyclopedia.

Hildegard of Bingen (c. 1098 – 17 September 1179), a German Benedictine abbess and polymath active in various fields as a writer, musical composer, philosopher, Christian mysticism, visionary, and as well a medical writer and practitioner.

Gerard of Cremona (c. 1114 – 1187) was an Italian translator working at the court of Castile in Toledo, Spain and was a prominent figure in the Toledo School of Translators for translating Ptolemy's Almagest as well as Euclid's Elements from Arabic to Latin.R. W. Southern, The Making of the Middle Ages, New Haven: Yale University Press, 1953, p. 64-65; L. D. Reynolds and Nigel G. Wilson, Scribes and scholars: A guide to the transmission of Greek and Latin literatureOxford: Clarendon Press, 1974, p. 106.For a list of Gerard of Cremona's translations see: Edward Grant (1974) A Source Book in Medieval Science, (Cambridge: Harvard Univ. Pr.), pp. 35-8 or Charles Burnett, "The Coherence of the Arabic-Latin Translation Program in Toledo in the Twelfth Century," Science in Context, 14 (2001): at 249-288, at pp. 275-281.

Averroes (1126-1198), a towering Andalusian polymath who wrote extensively on medicine, physics, and astronomy. His massive commentaries on Aristotle deeply influenced European universities.

Maimonides (1135/38-1204), a Sephardic Jewish philosopher and physician born in Cordoba, who published definitive texts on toxicology, pharmacology, and mental health that influenced both Islamic and Christian medical traditions.

Robert Grosseteste (1168–1253), Bishop of Lincoln, was the central character of the English intellectual movement in the first half of the 13th century and is considered the founder of scientific thought in Oxford. He had a great interest in the natural world and wrote texts on the mathematical sciences of optics, astronomy and geometry. In his commentaries on Aristotle's scientific works, he affirmed that experiments should be used in order to verify a theory, testing its consequences. Roger Bacon was influenced by his work on optics and astronomy.A. C. Crombie, Robert Grosseteste and the Origins of Experimental Science 1100–1700, (Oxford: Clarendon Press, 1971)

Fibonacci (1170-1250), an Italian mathematician who introduced the Fibonacci sequence and Hindu-Arabic numerals to the Western world through his groundbreaking work, Liber Abaci.considered to be "the most talented Western mathematician of the Middle Ages".

Vincent of Beauvais (1184/94-1264), a French Dominican friar who compiled the Speculum Maius, the largest and most comprehensive encyclopedia of natural history, geology, and agriculture written in the medieval Christian world.