The "younger house" of this dynasty began with the fourth rule to bear its dynastic name, a son of Alberto Azzo II, duke of Este, while the "elder house," of this dynasty appears to originate with a man whose daughters Judith and Emma married Louis the Pious and Louis the German, respectively.
The infant emperor of Russia Ivan VI was a male-line descendant of this dynasty's Brunswick-Wolfenbuttel branch. The "younger house" of this dynasty began with the fourth rule to bear its dynastic name, a son of Alberto Azzo II, duke of Este, while the "elder house," of this dynasty appears to originate with a man whose daughters Judith and Emma married Louis the Pious and Louis the German, respectively. Rulers from this family included Rudolf I of Burgundy, while another ruler of this dynasty went to war against his former wife Matilda of Tuscany, and this dynasty included a duke of Saxony who was atypically friendly with Frederick Barbarossa named Henry the Lion. This family's Hanoverian branch produced the royal line of England beginning with George I, and their chief medieval stronghold was Bavaria. For ten points, identify this German dynasty, whose rivalry with the Hohenstaufen emperors caused them to be viewed as supporters of the papacy in Italy.
The infant emperor of Russia Ivan VI was a male-line descendant of this dynasty's Brunswick-Wolfenbuttel branch.
Welf or Guelph