Marnix van St. Aldegonde studied theology under Calvin and Beza at Geneva and, returning to the Netherlands in 1560, threw himself energetically into the cause of the Reformation, taking an active part in the compromise of the nobles in 1565 and the assembly of St Trond. He made himself conspicuous by issuing a pamphlet in justification of the iconoclasts who devastated Flanders in 1566, and on Alva's arrival next year had to fly the country. After spending some time in Friesland and in the Palatinate he was in 1570 taken into the service of William, prince of Orange, and in 1572 was sent as his representative to the first meeting of the States-General assembled at Dordrecht.
In 1573 he was taken prisoner by the Spaniards at Maaslandsluys, but was exchanged in the following year. He was sent as the representative of the insurgent provinces to Paris and London, where he in vain attempted to secure the effective assistance of Elizabeth I. In 1578 he was at the diet of Worms, where he made an eloquent but fruitless appeal for aid to the German princes. Equally vain were his efforts in the same year to persuade the magistrates of Ghent to cease persecuting the Catholics in the city. He took a conspicuous part in arranging the Union of Utrecht, and in 1583 was chosen burgemeester of Antwerp. In 1585 he surrendered the city, after a 13 months' siege, to the Spaniards. Violently attacked by the English and by his own countrymen for this act, he retired from public affairs and, save for a mission to Paris in 1590, lived henceforth in Leiden or on his estate in Zeeland, where he worked at a translation of the Bible. He died at Leiden on the 15th of December 1598.
St Aldegonde, or Marnix (by which name he is very commonly known), is celebrated for his share in the great development of Dutch literature which followed the classical period represented by such writers as the poet and historian Pieter Hooft. Of his works the best known is the Roman Bee-hive (De roomsche byen-korf), published in 1569 during his exile in Friesland, a bitter satire on the faith and practices of the Roman Catholic Church. This was translated or adapted in French, German and English.
As a poet, St Aldegonde is mainly known through his admirable metrical translation of the Psalms (1580), and the Dutch national anthem Wilhelmus van Nassouwe is also ascribed to him. His complete works, edited by Lacroix and Quinet, were published at Brussels in 7 vols. (1855-1859), and his religious and theological writings, edited by Van Turenenbergen, at Paris, in 3 vols. (1871-1891).
See E Quinet, Marnix de St Aldegonde (Paris, 1854); Juste, Vie de Marnix (The Hague, 1858); Frédéricq, Marnix en zijnenederlandsche geschriften (Ghent, 1882); Tjalma, Philips van Marnix, heer van Sint-Aldegonde (Amsterdam, 1896).