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.

1240.  Emperor Frederick II advances against Pope Gregory IX and threatens Rome.  The Pope declares a crusade against him.

Batu Khan, at the head of Mongols of the Golden Horde, overruns and devastates Russia.

On the Neva, Alexander, Prince of Novgorod, gains a great victory over the Swedes.

1241.  Hamburg and Lubeck form an alliance to protect their commerce.  See “RISE OF THE HANSEATIC LEAGUE,” vi, 214.

Central Europe is invaded by the Mongols, or Tartars, who vanquish the Silesians, Poles, and Teutonic Knights at Wahlstatt; they defeat the Hungarians on the Sajo.

A Pisan and Sicilian fleet, by order of Frederick II, captures twenty-two Genoese galleys in which cardinals, prelates, and ambassadors, summoned by the Pope, were proceeding to hold a council at Rome; the prisoners were held at Naples and Apulia.

1242.  Aldermen first elected in London.

Asia Minor is invaded by the Mongols.

Alexander Nevski, son of Jaroslav, defeats the Swedes and Knights
Swordbearers at Lake Peipus.

1243.  Frederick II urges the cardinals to appoint a pope; he releases some of his prisoners to attend the conclave.

1244.  Jerusalem is stormed and sacked by the Kharesmians.

Pope Innocent IV escapes from Rome and fixes his court at Lyons.  Earliest use of the word “parliament” in England.

1245.  Thirteenth general council (Lyons) convened by Pope Innocent IV; it proclaims the deposition of Frederick II.  A new crusade is ordered.

End of the Babenberg dynasty in Austria.

1246.  Ferdinand, assisted by the Moors of Granada, lays siege to Seville.

1247.  Parma, recovered by the papal party, is besieged by Frederick II.

1248.  First crusade of Louis IX of France.  See “Louis IX LEADS THE LAST CRUSADE,” vi, 275.

Seville is wrested from the Moors by St. Ferdinand of Leon and Castile.

Emperor Frederick II compelled to raise the siege of Parma.

1249.  Damietta is captured by the crusaders.