The first part of this age was marked by the consolidation of Roman knowledge in the histories of Plutarch and the Almagest of Ptolemy and the medicine of Galen, and the wide adoption of the Stoic philosophy including by the emperor Marcus Aurelius. But it was also the age when Christianity began to take hold, and the midpoint of this age, 350, is close to the date when it became the state religion of the Roman empire.
Plutarch (c.46 - c.120) biographer, historian, encyclopedist.
Epictetus (c.55 - 135) freed slave, stoic philosopher.
Zhang Heng (78 - 139) Chinese astronomer.
Claudius Ptolemy & & (c.85 - 165). made astronomical observations 127-141, compiled and systematised the knowledge of his day: Harmonics on music, Optics on light, including angles of refraction for several media, Geographia including map projections, Tetrabiblos on astrology, Planetary Hypothesis on cosmology, Syntaxis or 'Almagest' on astronomy.
Lucius Apuleius (c.120 - 180), satirical author of The Golden Ass & and the Apology a speech in defence of a slander against him.
Marcus Aurelius & & & & & (121 - 180) Roman consul (140) and emperor (161), stoic philosopher Meditations & & 167.
Galen, aka Claudius Galenus of Pergamum & & & & & (c.130 - c.201), physician to gladiators and emperors, including Marcus Aurelius, 83 treatises extant including On the Natural Faculties, Exhortation to Study the Arts, Diagnosis in Dreams and 15 commentaries on Hippocrates.
The Nine Chapters c.210, a Chinese mathematical work.
Diophantus (fl.3rd century) Alexandrian mathematician, Arithmetica introduced 'diophantine equations' in theory of numbers.
Aurelian (212 - 275), Roman emperor 270. Defeated Zenobia of Palmyra (who had conquered Egypt 269 and most of Asia Minor).
Diogenes Laertius, biographer of the Greek philosophers.
Diocletian (245 - 313), Roman emperor 284-305.
Arius (250 - 336), theologian.
Eusebius of Caesaria (c.264 - 340), theologian, Ecclesiastical History 324, not averse to 'pious forgery'.
Constantine I (274 - 337), Roman emperor 323, made christianity the state religion 324, adopted Nicene creed 325, made Constantinople (Byzantium) the capital 330.
Athanasius (296 - 373), theologian.
Ambrose (339 - 397) bishop of Milan 374, introduced hymns, ritual and codified plain-chant.
Jerome, aka Eusebius Sophronius Hieronymus (c.342 - 420), Vulgate bible in Latin 386.
Theodosius I (c.346 - 395), Roman emperor 379.
Augustine of Hippo & & & & & (354 - 430) - christian 'neoplatonist' philosopher and theologian.
Pelagius, aka Morgan (c.360 - c.420), theologian, rejected the doctrines of original sin and predestination.
Alaric I (370 - 410) king of the Visigoths 395, sacked Rome 410.
Hypatia (c.375 - 415), Alexandrian philosopher, murdered by a christian mob, encouraged by archbishop Cyril of Alexandria (376 - 444) who also expelled the Jews, and persecuted Nestorius, patriarch of Constantinople 428 - 431 (d.451), for heresy.
Attila (c.406 - 453) king of the Huns 434.
Proclus (411 - 485).
Patrick (5th century), missionary of christianity to Ireland 432.
450 Tsu Ch'ung-Chih and Tsu K^eng-Chih compute pi to six decimal places
Aryabhata the Elder (476 - 550) Aryabhatiya & Indian mathematician and astronomer, uses Sanskrit syllabic numeration.
"In 499, the mathematician-astronomer Aryabhata propounded a detailed model of the heliocentric Solar System of gravitation, where the Planets rotate on their axes causing day & night and follow elliptical orbits around the Sun causing year, and where the Planets and the Moon do not have their own light but reflect the light of the Sun. Aryabhata also correctly explained the causes of the solar and lunar eclipses and predicted their times, gave the radii of planetary orbits around the Sun, and accurately measured the lengths of the day, sidereal year, and the Earth's diameter and circumference." (?? unconfirmed claim)
550 Hindu mathematicians give zero a numeral representation in a positional notation system
Columba, aka Colm (521 - 597 Iona), missionary of christianity in Scotland.