Welf remained in charge of his Italian duchies until 1173, while Christian, Archbishop of Mainz, was imperial vicar.

During the interregnum, imperial power was exercised by two imperial vicars.

His reward was the title of imperial vicar in Lombardy (1274).

An imperial vicar was a prince charged with administering all or part of the Holy Roman Empire on behalf of the Emperor.

In 1356 he was named imperial vicar by emperor Charles IV.

Henry had immediately begun appointing imperial vicars throughout the newly-acquired province over the objections of both the Tuscan cities and the papacy.

Archduke Johann of Austria was chosen as a temporary head of state ("Reichsverweser" i.e. imperial vicar).

Ulrich of Attems, 1139-1152 (imperial vicar of Tuscany and Spoleto)

During his father's campaign in Italy 1401-1402 Louis served as imperial vicar.

Nicholas moved on to Grosseto and then to Pisa, where he was guarded by the imperial vicar.