The main source for biographical information about Lamport is his own declaration before the Inquisition; it is difficult to tell how much of it is true. William Lamport was born in either 1611 (according to his brother) or 1615 (other sources) in Wexford, Ireland to a family of Catholic merchants. He received Catholic education from Jesuits in Dublin and London, and then at an Irish college in the great pilgrimage site of Santiago de Compostela, in northwest Spain. Since the Protestant monarchy in England increasingly restricted opportunities to Catholics, a number of colegios for Irishmen were set up in Spain. There were longstanding ties between Catholic Ireland and Spain, the staunch defender of Catholicism in Europe. Spain recognized Irish nobles on equal footing as Spaniards, and Irish could claim Spanish citizenship.