Joannes Molanus (1533–1585), often cited simply as Molanus, is the latinized name of Jan Vermeulen or Van der Meulen, an influential Counter Reformation Catholic theologian of Louvain University, where he was Professor of Theology, and Rector from 1578. Born at Lille (a city in the County of Flanders, then under Habsburg rule), he was a priest and canon of St. Peter's church in Louvain, where he died.
He wrote numerous books, several only published posthumously. He is best known for his De Picturis et Imaginibus Sacris, pro vero earum usu contra abusus ("Treatise on Sacred Images"). This was published in 1570, four years after the Iconoclastic Fury had swept through the Low Countries, and it defended the production and use of devotional images, but with many restrictions to prevent abuses. Five further, enlarged, editions of this appeared between 1594 and 1771, and a modern French translation was published in 1996. He was also lead editor of an edition of the works of Saint Augustine (Antwerp, Plantin Press, 1566–1577), and wrote a manuscript history of Louvain that was printed in two volumes in 1861, edited by P. F. X. de Ram.
Molanus was born in Lille, in Walloon Flanders, in 1533, the son of Hendrik Vermeulen and Anna Peters. His father was from Holland and his mother from Brabant.
He matriculated at Louvain University on 27 February 1554, graduating in the Liberal Arts in 1558 and as Doctor of Theology in 1570. He became a canon of St. Peter's Church, Leuven and a professor of Theology, serving both as dean of the Faculty of Theology and as rector of the university. In 1579 he was appointed president of King's College.