Editing 421 (section)

==== Roman Empire ====
* [[February 8]] &ndash; [[Constantius III]] is appointed co-emperor (''[[Augustus (title)|Augustus]]'') with his ineffectual brother-in-law, [[Honorius (emperor)|Honorius]], and becomes the real ruler of the [[Western Roman Empire]].
* [[March 25]] &ndash; [[Venice]] is founded at twelve o'clock noon (according to legend) with the dedication of the first church, [[San Giacomo di Rialto|San Giacomo]], at the islet of [[Rialto]] ([[Italy]]).  
* [[June 7]] &ndash; Emperor [[Theodosius II]] marries [[Aelia Eudocia]], a woman of Greek origin. The [[wedding]] is celebrated at [[Constantinople]] with [[chariot racing]] in the [[Hippodrome of Constantinople|Hippodrome]].<ref>{{Cite book |last=Holum |first=Kenneth G. |title=Theodosian Empresses: Women and Imperial Dominion in Late Antiquity |date=1989-10-25 |publisher=University of California Press |isbn=978-0-520-06801-8 |pages=115 |language=en}}</ref>
* [[September 2]] &ndash; Constantius III dies suddenly of an illness; his wife [[Galla Placidia]] becomes, for the second time, a [[widow]]. She departs with her children [[Justa Grata Honoria|Grata Honoria]] and [[Valentinian III|Valentinian]] to the court of Constantinople.
* [[Castinus campaign against the Franks]]: A Roman army under command of [[Castinus]] fights against the Franks in Northern Gaul.