Coal first discovered near Newcastle, England.
1234. Pope Gregory IX driven from Rome by the senate and citizens, who resist his temporal power and seize his revenues; he appeals to Emperor Frederick II for assistance.
1235. Marriage of Frederick II to Isabella, sister of Henry III of England. He forbids the extravagant payments usually made on such occasions to buffoons, mimics, and players.
1236. Ezzelino da Romano, the Ghibelline leader, joins Emperor Frederick II in war upon the Lombard League.
Cordova recovered from the Moors by Ferdinand III of Leon and Castile.
1237. Battle of Cortenuova; victory of Frederick II over the Lombard League.
Union of the Knights Swordbearers, founded 1186, with the Teutonic
Knights in Prussia; they extend their conquests.
1238. League of Venice, Genoa, and Pope Gregory IX against Frederick II.
Establishment of the Moorish kingdom of Granada, Spain.
1239. Frederick II, having married his natural son, Enzio, to Adelaide, heiress of the two principalities of Torri and Gallura, creates him king of Sardinia. Pope Gregory IX claims the island and excommunicates the Emperor, denouncing him as a heretic and absolving his subjects from their allegiance.