December 18, 218 BC Second Punic War: Battle of the Trebia – Hannibal's Carthaginian forces defeated those of the Roman Republic. 1271 – Kublai Khan renames his empire "Yuan" (元 yuán), officially marking the start of the Yuan Dynasty of Mongolia and China. 1352 Innocent VI became Pope. Innocent was a law professor before taking holy orders. As pope, he made reforms to the papal Curia at Avignon.