September 11 is the 254th day of the year (255th in leap years) in the Gregorian calendar; 111 days remain until the end of the year. Events. Pre-1600. 9 – The Battle of the Teutoburg Forest ends: The Roman Empire suffers the greatest defeat of its history and the Rhine is established as the border between the Empire and the so-called barbarians for the next four hundred years. 1185 – Isaac II Angelos kills Stephen Hagiochristophorites and then appeals to the people, resulting in the revolt that deposes Andronikos I Komnenos and places Isaac on the throne of the Byzantine Empire.
https://en.wikipedia.org/wiki/September_11