(b Copenhagen, 1716; d Hannover, 4 March 1776). German painter of Danish birth. He trained with his father, Johann Georg Ziesenis (1681-1748); he became a German citizen in 1743 and subsequently was appointed court painter to Herzog Christian von Pfalz-Zweibrecken in Zweibrecken and, later, Mannheim. In the early 1750s he overcame his technical shortcomings by studying Flemish art, particularly the work of Rubens and van Dyck. He also introduced a new genre, the private court portrait. His portrait of Karl Philipp Theodor, Kurferst von der Pfalz (1757; Munich, Alte Pin.) is original in its intimate view of a nobleman posed at leisure in casual dress, seated in his private study.