Editing September 21 (section)

===Pre-1600===
* [[455]] &ndash; Emperor [[Avitus]] enters [[Italy]] with a Gallic army and consolidates his power.<ref>{{cite book|last=Maenchen-Helfen|first=Otto|title=The World of the Huns: Studies in Their History and Culture|location=Berkeley|publisher=University of California Press|date=1973|isbn=9780520015968|url=https://books.google.com/books?id=MKXeEAAAQBAJ|page=145|postscript=none}}; {{cite book|last=Mathisen|first=Ralph W.|title=Studies in the History, Literature and Society of Late Antiquity|location=Amsterdam|publisher=A.M. Hakkert|date=1991|isbn=9789025609832|url=https://books.google.com/books?id=6cVmAAAAMAAJ&q=Avitus+%22September+21%22+%22455%22|page=139}}</ref>
*[[1170]] &ndash; [[Anglo-Norman invasion of Ireland]]: The [[Kingdom of Dublin]] falls to [[Anglo-Normans|Anglo-Norman]] invaders.<ref>{{cite book|last=State|first=Paul F.|title=A Brief History of Ireland|location=New York|publisher=Facts On File|date=2009|isbn=9780816075164|url=https://books.google.com/books?id=l24l91AqAjYC|page=66}}</ref>
*[[1217]] &ndash; [[Livonian Crusade]]: The Estonian leader [[Lembitu]] and Livonian leader [[Caupo of Turaida]] are killed in the [[Battle of St. Matthew's Day]].<ref>{{cite book|last=Rebane|first=Peep Peter|chapter=From Fulco to Theoderic: The Changing Face of the Livonian Mission|editor-last=Murray|editor-first=Alan V.|title=The North-Eastern Frontiers of Medieval Europe: The Expansion of Latin Christendom in the Baltic Lands|location=New York|publisher=Routledge|date=2016|isbn=9781409436805|url=https://books.google.com/books?id=KgokDwAAQBAJ|page=99}}</ref>
*[[1435]] &ndash; The [[Congress of Arras|Treaty of Arras]] is promulgated, causing [[Burgundian State|Burgundy]] to switch sides in the [[Hundred Years' War]].<ref>{{cite book|last=Russell|first=Joycelyne Gledhill|title=The Congress of Arras, 1435: A Study in Medieval Diplomacy|location=New York|publisher=Biblo and Tannen|date=1972|isbn=9780819602817|url=https://books.google.com/books?id=YEiOso5yIIoC|pages=viii–ix, 179}}</ref>