See Michael Newman, Die deutschen Porzellan-Manufakturen im 18. Jahrhundert (Brunswick, 1977), Vol. II, p. 239, fig. 143 for a very similar plaque with the same sitter. Johann Joachim Bellermann (1745-1824) was a Professor of Philosophy and Theology at the University of Erfurt, and later became Professor of Theology at the University of Berlin. He was step brother to Rosina Nonne.