The patron saint of Bollate is Bishop Saint Martin, celebrated on 11 November: the occasion is still celebrated on this date today, and the town's collegiate church is dedicated to the saint.
Bollate gave its name to the old pieve of Bollate, or pieve of San Martino, an ecclesiastical district of the archdiocese of Milan that also coincided with an administrative unit of the Duchy of Milan, of which the town was the capital.