Science & Discovery in the 4th century

16 sourced entries, 320 CE to 395 CE, oldest first. Also see Science & Discovery across every century or everything else in the 4th century.

• 320October 18 – Pappus of Alexandria, Greek philosopher, observes an eclipse of the sun and writes a commentary on The Great Astronomer (Almagest).source
• 336December 25 – The first celebration of Christmas is recorded.source
• 351In India, a new process makes possible the extraction of sugar from sugarcane.source
• 352The earliest sighting of a supernova occurs in China.source
• 354The Roman Calendar of 354, an illuminated manuscript, is drawn up and becomes the earliest dated codex.source
• 363April 20 – The planet Venus occults the planet Jupiter.source
• 364Theon of Alexandria, Greek mathematician, observes a solar eclipse (June 16) and a lunar eclipse (November 25).source
• 366The Tabula Peutingeriana, a map showing Roman possessions and roads, is created about this time.source
• 367In the region of the constellation Perseus, a star not visible to the naked eye, and 1,533 light years distant from Earth, explodes in a nova. The light from the star, now called GK Persei, was first detected on Earth on February 21, 1901.source
• 380Important works on mathematics and astronomy are written in Sanskrit.source
• 385Ammianus Marcellinus begins writing a history, in the style of Tacitus, covering the years AD 96–378.source
• 387Oribase, Greek doctor, publishes a treatise on paralysis and bleedings.source
• 391Flames destroy the great Library of Alexandria, established in the Mouseion in the fourth century BC. Among the items lost in the fire are works of science, including parchments by the Greek astronomer Aristarchus of Samos asserting that the Earth orbits the Sun, and dozens of dramatic works by Euripides and Sophocles.source
• 393Chinese astronomers observe the guest star SN 393.source
• 394The last known hieroglyphic inscription, known as the Graffito of Esmet-Akhom, is written in Philae, Egypt.source
• 395Russian astronomer Nikolai Alexandrovich Morozov claimed that Revelation to John could be astronomically dated to September 30, 395.source