Hugo de Groot (Grotius), copy after M.J. van Miereveld, 1631. In 1607 the internationally renowned jurist Hugo de Groot (1583-1645), known also by his Latinised name Grotius, published Mare liberum, in which he argued for free trade at sea. In a later work, De iure belli ac pacis (on the laws of war and peace) he laid what many consider to be the foundation of international law. Like Johan van Oldenbarnevelt, Hugo de Groot was arrested in 1618 after a confrontation with the stadholder, Prince Maurice. De Groot received a life sentence and was imprisoned in Loevestein castle. In 1621 he escaped and fled to France. During a short return to the Republic he posed for the painter Van Miereveld. This is one of the many copies of that portrait.