Philip of Burgundy
Between 1515 and 1524 he was in service of Philip of Burgundy. This illegitimate son of Philip the Good was first Admiral of Flanders and later bishop of Utrecht. In Utrecht, Geldenhouwer came into contact with the protestantism of Luther. After Philip's death, he travelled through the Low countries and Germany, and visited amongst others the city of Wittenberg to hear Luther. In 1526 he left the Augustinians and married.