Marnix of St. Aldegonde was born at Brussels, the son of Jacob of Marnix. He studied theology under John Calvin and Theodore Beza at Geneva. Returning to the Netherlands in 1560, he threw himself into the cause of the Reformation, taking an active part in the compromise of the nobles in 1565 and the assembly of Sint-Truiden. He issued a pamphlet in justification of the iconoclastic movement Beeldenstorm which devastated many churches in Flanders in 1566, and on the Duke of Alba's arrival next year had to flee the country.
