636
Christians lose control of the Levant
On this day in 636 began the Battle of Yarmouk in which forces of the first Islamic Caliphate defeated a Byzantine army in what is now Syria. It was a long-held part of Byzantine strategy to avoid major winner-take-all battles but the arrival of a massive Arab army that had already rolled up Persian and Christian holdings in the Middle East forced the Byzantines to concentrate their forces. They were outmaneuvered and driven from the field leading to a rapid Islamic conquest of the eastern shore of the Mediterranean, territory that would not be regained until the First Crusade in 1099.
A plethora of other Church-related activity also took place on this day.
747
Frankish co-ruler Carloman retires to a monastery leaving his brother Pepin the Short in charge. Within a few years Pepin will win papal approval for deposing the Merovingian dynasty and setting up the Carolingian line. In return Pepin will invade Italy to defeat enemies of the pope and grant the Bishop of Rome the lands that become the Papal States.
1070
Lanfanc, a Benedictine monk from Italy, will be named Archbishop of Canterbury. Working with the recently-victorious William the Conqueror he will reform the English church, cutting down on corruption and sexual immorality in the clergy. He will also resist papal pressure and avoid entangling England in the battles between church and state that raged on the Continent.
1248
The cornerstone for the most striking of all Gothic cathedrals will be laid in Cologne. The building would house the relics of the Three Magi and be finished only in 1880.
1309
The Knights of St John seize the island of Rhodes and use it as a base against Islamic states in the eastern Mediterranean. They will stay in their huge fortress until being driven out by Suleiman the Magnificent in 1521.
1483
Pope Sixtus IV consecrates the Sistine Chapel.
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