1266
Aquinas begins Summa Theologiae
At the papal studium in Rome, Thomas Aquinas began work on his massive theological synthesis. Structured as a series of questions and disputations, the Summa would remain incomplete at his death but stand as the most ambitious Christian systematic work of the Middle Ages. Its three parts addressed God's nature, humanity's moral journey, and Christ's role as the way to salvation, encompassing all of Christian doctrine.
Berke-Hulagu war splits the Mongol world
The Golden Horde and the Ilkhanate fought a pitched battle at the Terek River in the Caucasus, the first open war between Mongol khanates. Berke, a Muslim convert outraged by Hulagu's destruction of Baghdad, allied with the Mamluks against his own cousin. The unified empire Genghis had built was fracturing irreparably.
Baibars storms Safed from the Templars
The Mamluk sultan captured the Templar castle of Safed after a month's siege, having promised the garrison safe passage. When they surrendered, he had every knight beheaded on the surrounding hills. The Crusader states lost a key fortress and any trust in Baibars's word. The treachery at Safed became a defining episode in the final chapter of the Crusades, cited by chroniclers on both sides.
Charles of Anjou kills Manfred at Benevento
Invited south by the papacy to crush the Hohenstaufen, Louis IX's brother routed Manfred of Sicily on a plain near Benevento. Manfred died on the field; his body was buried in unconsecrated ground under a cairn of stones. Charles assumed the crown of Sicily. His harsh Angevin rule would provoke the Sicilian Vespers sixteen years later, a revolt that split his Mediterranean kingdom in two.