House of Visconti
In the 10th-century, the archbishops of Milan became feudatory of the Emperor extending his jurisdiction to all North-West Italy. The most distinguished of these was Ariberto da Intimiano (1018–45). As the power of the burghers grew, that of the archbishops waned, and with it the imperial authority which the prelate represented, and since the 12th century Milan became a Guelph town who fought the Emperor. The archbishop Ottone Visconti in the 13th-century caused himself to be proclaimed perpetual lord, thus putting an end to the Republic of Milan and establishing the power of the House of Visconti who ruled the Duchy of Milan from 1277 to 1447.