The stadholders of Friesland were not the descendants of William of Orange, but of his brother Jan. Ernst Casimir, Jan’s son, moreover, was also stadholder of Groningen and Drenthe. He is shown here in military regalia, with a buff jerkin, cuirass, boots with spurs, and a staff of office. The style of the clothing suggests that the portrait originated around 1630; it could have been painted after his violent death in 1632.