Year 400 (CD) was a leap year starting on Sunday of the Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Stilicho and Aurelianus (or, less frequently, year 1153 Ab urbe condita). The denomination 400 for this year has been used since the early medieval period, when the Anno Dominicalendar era became the prevalent method in Europe for naming years.
A riot breaks out in Constantinople; the Great Palace is burned to the ground. Gainas, a Gothic leader, attempts to evacuate his soldiers out of the city, but 7,000 armed Goths are trapped and killed by order of Arcadius. After the massacre, Gainas tries to escape across the Hellespont, but his rag-tag ad hoc fleet is destroyed by Fravitta, a Gothic chieftain in imperial service.
Winter – Gainas leads the remaining Goths back to their homeland across the Danube. They meet the Huns and are defeated; the Hunnic chieftain Uldin sends the head of Gainas to Constantinople, where Arcadius receives it as a diplomatic gift.
Caelius Aurelianus, Roman physician, is practising his work "De morbis acutis et chronicis" (Concerning Acute and Chronic Illness), a guide to acute and chronic diseases.
^Kelly, Christopher (2010). The End of Empire. New York: W.W. Norton & Company. p. 76. ISBN978-0-39333-849-2.
^Kidder, Jonathan Edward (1977). Ancient Japan. Oxford: Elsevier-Phaidon. p. 146. ISBN978-0-72900-047-5.
^Maas, Philipp André (2004). Samādhipāda das erste Kapitel des Pātañjalayogaśāstra zum ersten Mal kritisch ediert [Samādhipāda critically edited the first chapter of the Pātañjalayogaśāstra for the first time] (in German). Aachen: Shaker. ISBN3832249877.
