House of Welf

The House of Welf (also Guelf or Guelph) is a European dynasty that has included many German and British monarchs from the 11th to 20th century and Emperor Ivan VI of Russia in the 18th century. The originally Franconian family from the Meuse-Moselle area was closely related to the imperial family of the Carolingians.

The (Younger) House of Welf is the older branch of the House of Este, a dynasty whose earliest known members lived in Veneto and Lombardy in the late 9th/early 10th century, sometimes called Welf-Este. The first member was Welf I, Duke of Bavaria, also known as Welf IV. He inherited the property of the Elder House of Welf when his maternal uncle Welf III, Duke of Carinthia and Verona, the last male Welf of the Elder House, died in 1055.

Welf IV was the son of Welf III's sister Kunigunde of Altdorf and her husband Albert Azzo II, Margrave of Milan. In 1070, Welf IV became Duke of Bavaria.

Welf II, Duke of Bavaria married Countess Matilda of Tuscany, who died childless and left him her possessions, including Tuscany, Ferrara, Modena, Mantua, and Reggio, which played a role in the Investiture Controversy. Since the Welf dynasty sided with the Pope in this controversy, partisans of the Pope came to be known in Italy as Guelphs (Guelfi).

The first genealogy of the Welfs is the Genealogia Welforum, composed shortly before 1126. A much more detailed history of the dynasty, the Historia Welforum, was composed around 1170. It is the earliest history of a noble house in Germany.

Henry IX, Duke of Bavaria, from 1120 to 1126, was the first of the three dukes of the Welf dynasty called Henry. His wife Wulfhild was the heiress of the house of Billung, possessing the territory around Lüneburg in Lower Saxony. Their son, Henry the Proud, was the son-in-law and heir of Lothair II, Holy Roman Emperor and became also Duke of Saxony on Lothair's death.

Lothair left his territory around Brunswick, inherited from his mother of the Brunonids, to his daughter Gertrud. Her husband Henry the Proud became then the favoured candidate in the imperial election against Conrad III of the Hohenstaufen. Henry lost the election, as the other princes feared his power and temperament, and was dispossessed of his duchies by Conrad III.

Henry's brother Welf VI (1115–1191), Margrave of Tuscany, later left his Swabian territories around Ravensburg, the original possessions of the Elder House of Welf, to his nephew Emperor Frederick I, and thus to the House of Hohenstaufen.