 The figure of the Borromean rings, which forms part of the family’s coat of arms, is well known in the diverse fields of topology, psychoanalysis and theology.Around 1300 this was one of a number of merchant families in San Miniato to carry the name "'Buon Romei'" (or 'Borromei') because of their origins from Rome.The first member of the family to come to prominence was Filippo who, backed by Holy Roman Emperor Charles IV and Gian Galeazzo Visconti (later to become Duke of Milan), led the Ghibellines of San Miniato in their 1367 revolt against the Florentine Guelphs.