The founder of the family was William I of Montferrat, a Frank, who came over to Italy in 888 or 889 to aid his fellow Frank Guy III of Spoleto in a quest for the Iron Crown of Lombardy. His son Aleram was the first to carry the title marchio or margrave.
By the 12th century, the Aleramici were one of the most considerable in Piedmont, related to the Capetians and the Hohenstaufen. Members of the family participated frequently in the Crusades, and became kings and queens of Jerusalem. They also married into the Byzantine imperial families of Comnenus, Angelus, and Palaeologus and, as a result of the Fourth Crusade, founded the Latin Kingdom of Thessalonica.
Conrad of Montferrat (or Conrad I of Jerusalem) (Italian: Corrado di Monferrato; Piedmontese: Conrà ëd Monfrà) (mid-1140s – 28 April 1192) was a northern Italian nobleman, one of the major participants in the Third Crusade. He was the de facto King of Jerusalem, by marriage, from 24 November 1190, but officially elected only in 1192, days before his death. He was also marquis of Montferrat from 1191.
At the end of the 11th century the family was split into two main branches: one ruled Montferrat until 1305; the other (Del Vasto) ruled the south of Piedmont and western Liguria. In the middle of 12th century the Del Vasto family branched again into several lines, governing smaller marquisates, such as Saluzzo (from 1135 to 1548), Finale (ruled by the Del Carretto from 1135 to 1602), Ceva, Busca and Clavesana. The Del Carretto had many collateral lines in Piedmont, in Sicily and apparently even in France (de Charette). On the other hand the Lancia are a branch of the marquesses of Busca.