Council of Chalcedon
Church council in 451, at which Monophysitism was condemned again, and the idea of Two Natures Coexisting in One Person was promulgated as official doctrine: the Chalcedonian Definition.
Battle of Soissons
Clovis’s defeat of Syagrius in 486.
Battle of Vouille
Clovis's defeat of Arian Visigoths in 507.
Nika Revolt
Revolt of Blues and Greens in Constantinople against Justinian in 532. Put down by Belisarius, Narses, and Munda.
Bubonic Plague
Plague afflicting Mediterranean Basin from 542-550, and then at intervals in next 50 years. Up to 33 percent mortality rate.
Battle of Busta Gallorum/Battle of Taginæ
Byzantine final defeat of Goths in 552 CE. Narses led Romans, and Totila led Goths.
Edict of Clothar
Edict in 614 in which Clothar committed to only appoint royal officials from a particular region’s local count.
Battle of the Yarmuk
Islamic armies defeat Byzantine troops in present-day Syria-Jordan in 636.
Battle of al-Qadisiyya
Islamic armies 636 defeat Sassanian forces, opening up Persia, and leading to the Sassanian downfall.
Council of Whitby
In the 650s-660s, both Irish and Roman missionaries were converting in England. Given differences in ritual observance, King Oswy held the Council of Whitby in 664, where the decision was made to follow the Roman rite.
Battle of Tours
Battle in Poitiers in 732, where Charles Martel stopped Muslim penetration into France.
Battle of Fontenoy
Louis the Pious’s oldest son Lothair was slated to get most of the realm. In 840 his two younger brothers Charles the Bald and Louis the German combined to fight him at the Battle of Fontenoy. Losses were tremendous, yet the results required compromise. Charles the Bald received western regions from forty miles east of Paris to the southwestern Marches and stretching from the English Channel to the Mediterranean. Louis the German received eastern districts from the Marches beyond the Elbe to just outside Strasbourg, and from Denmark in the north to the Adriatic in the south. Wedged in between this was Lothair's kingdom, stretching from the North Sea all the way past the papal States in Italy, with the Imperial capitals.
Battle of Edington
In 866, a large force of Danish Vikings invaded southeastern England, overrunning East Anglia, Northumbria, and Mercia by 877. They were stopped only by King Alfred the Great (r. 871-899) of Wessex, who defeated them at Edington in 878.
Battle of Dyle
Viking power began to wane, as German king Arnulf defeated them at Dyle in the Netherlands in 891.
Battle of Riade/Battle of Unstrut
In 933, Henry the Fowler refused further payments of tribute to the Magyars. When the Hungarians launched a massive punitive expedition, Henry routed it near the Unstrut river.
Battle at Lechfeld
Otto I’s defeat of the Magyars in 955. They ceased as a threat after that.
Occultation
Disappearance of last Shi’ite Imam in 980s.