400s

Centuries: 4th century - 5th century - 6th century

Decades: 350s - 360s - 370s - 380s - 390s - 400s - 410s - 420s - 430s - 440s - 450s

Years: 400 401 402 403 404 405 406 407 408 409

• Constantine III siezes control of the Roman garrison in Britain, declares himself emperor, and crosses into Gaul.
• August 22, 408 - Stilicho, military power behind the imperial throne, is executed. The Roman military is leaderless for several years until Constantius III becomes patrician.