Guelphs (gwĕlfs) [key], European dynasty tracing its descent from the Swabian count Guelph or Welf (9th cent.), whose daughter Judith married the Frankish emperor Louis I. Guelph III (d. 1055) was made (1047) duke of Carinthia and margrave of Verona. Without male heirs, he was succeeded by his nephew, Guelph IV, whose father was a member of the Italian house of Este. He became (1070) the first Guelph duke of Bavaria. His grandson, Henry the Proud, inherited the duchy of Saxony from Holy Roman Emperor Lothair II through his marriage to Lothair's daughter Gertrude. Henry's control of both Bavaria and Saxony made the Guelphs powerful rivals to the house of Hohenstaufen for the imperial title; when Conrad III of Hohenstaufen became German king in 1138 he deprived Henry of his duchies, and war ensued. Amity between the two dynasties was restored with the accession of Frederick I of Hohenstaufen as Holy Roman emperor in 1155. His mother, Judith, was the sister of Henry the Proud, and Frederick I thus united in his person the two chief rival houses of Germany. Frederick reconfirmed Henry the Lion, successor of Henry the Proud, as duke of Saxony and Bavaria. Later in Frederick's reign friction between the two developed, and in 1180, Frederick confiscated Henry's duchies; the Guelphs retained only Brunswick and Lüneburg. Henry's son Otto IV briefly became Holy Roman emperor but was deposed (1215). In 1235, Brunswick and Lüneburg were raised to the duchy of Brunswick under Henry's grandson Otto I of Brunswick. The line of Brunswick-Lüneburg or Hanover (see Hanover, house of) ascended (1714) the throne of Great Britain in the person of George I, but because of the Salic law of succession Hanover was separated (1837) from the British crown on the accession of Queen Victoria. After the annexation of Hanover by Prussia and the deposition (1866) of George V, last king of Hanover, the so-called Guelphic party was founded and unsuccessfully sought to restore the kingdom.
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