For families from the Azores, except Graciosa. Willem de Keersmaeker (Brugge, Flanders) had several children with his wife Mrs van der Haegen (also Flemish). After her death he moved with his children and his new wife Isabell de Zabuya to the Azores. He had another child Francisco da Silveira ( ou Casmaca) born in Faial. As was common in the XV century surnames could be translated. For some unknown reason it was the surname "van der Haegen" that was translated from Dutch to Portuguese at that time by about 1450. Willem de Keersmaeker is therefore the common ancestor of most people bearing the surname Silveira in the Azores, Brazil, North America and in general where people from the Azores settled bearing this surname.