Anciano en un sillón, posiblemente un retrato de Jan Amos Comenius

The title hedges, and for good reason. This may be Jan Amos Comenius, the exiled Moravian teacher who spent his last years in Amsterdam arguing that every child on earth, girls included, should be taught in their own language. Comenius and Rembrandt lived in the same city in the 1660s, both of them well past their prosperous years. Whoever the sitter is, Rembrandt paints him late and loose, the white beard and collar caught in a few broad strokes, the hands barely finished, the dark robe almost swallowing the chair. Rembrandt himself had four years left to live when he set this old man down.