The family descends from a Vermis, inhabitant of the area of Porta San Zeno and attested in 1174. In the following decades the filii de Vermo are mentioned, identifiable with Nicola, Iacobino, Gambarino and, perhaps, the causidicus Iohannis de Vermo. The first notable exponent, to whom we owe the social and political affirmation of the family, was precisely Nicola: an expert in law, he was involved in various municipal magistrates, coming out unscathed from the Ezzelian period.
In Verona and in other cities they had other important offices (mayor, captain of the people, governor), until the fourteenth century with Peter and starting from Luchino (+ 1367 in Constantinople) son of Peter, also began the activity of condottieri to service initially of the Visconti and of Venice. Jacopo (Verona 1350 - + Venice 1409) son of Luchino, lord of Sanguinetto, was also from 1379 at the service of the Visconti. He began to acquire fiefdoms in the territory of Bobbio (Zavattarello, Rocca d'Olgisio, Trebecco, Romagnese, Ruino, Pianello Val Tidone, Pecorara and Borgonovo Val Tidone), the nucleus of the future great lordship of the family and in 1387 was nominated by the Visconti vassallo of Bobbio . His son Luigi (+ 1449), at the service of Filippo Maria Visconti, count of Sanguinetto from 1433, in 1436 became lord of Voghera, Bobbio, Castel San Giovanni and Valsassina. Luigi's son, Pietro, was also General of the Milanese army under the Sforza family, but in 1485 he was assassinated, in the context of the troubles that brought to power Ludovico il Moro, who, adversary of the family for his loyalty to the previous Dukes, confiscated all the fiefs, despite the protests of Taddeo, Peter's surviving brother. It was not better to go under the French who replaced the Sforza; only the sons of Taddeo, Marcantonio and Federico, who returned to the Sforza thanks, had confirmation of the feuds (except Castel San Giovanni passed in the meantime to the Dukes of Parma and Piacenza). In 1516 the Marquisate of Bobbio was formed which united the feuds with the counties of Tortona and the lands of the Malaspina Lordship (the mandates of Varzi, Ottone, Torriglia and Santo Stefano d'Aveto). In 1530 the feuds of Bobbio and Voghera were divided between the two brothers, but always under the Marquisate of Bobbio.