Welf

The Welfs began as a Franconian clan kin to the Carolingians. When the elder male line ended with Duke Welf III of Carinthia in 1055, his estates passed to his nephew Welf IV of Este, who became Duke of Bavaria in 1070 and founded the Welf-Este house. The family backed the papacy in the Investiture Controversy, so the pope's Italian partisans took the name Guelphs from them.

Under Henry the Lion, Duke of Saxony from 1142 and Bavaria again from 1156, the house reached its medieval height: he founded Munich and made Brunswick his capital, but his breach with Frederick Barbarossa cost him both duchies in 1180. His son Otto IV, the only Welf emperor, was crowned in 1209 and ruined at Bouvines in 1214.

In 1235 Otto the Child received the Duchy of Brunswick-Lüneburg, split in 1269 into Brunswick and Lüneburg lines whose branches still ruled Saxon principalities in 1337. A Hanover branch gained the electoral dignity in 1692 and the British throne with George I in 1714.