the ambrosian rite, also called the milanese rite, is a catholic western liturgical rite. the rite is named after saint ambrose, a bishop of milan in the fourth century. the ambrosian rite, which differs from the roman rite, is used by some five million catholics in the greater part of the archdiocese of milan, italy (excluding, notably, the areas of monza, treviglio, trezzo sull'adda and a few other parishes), in some parishes of the diocese of como, bergamo, novara, lodi and in about fifty parishes of the diocese of lugano, in the canton of ticino, switzerland.