Johnson moved to The Hague in 1851. On November 20, 1851, he wrote to Andrew Warner of the American Art-Union, “I am at present . . . at the Hague, where I find I am deriving much advantage from studying the splendid works of Rembrandt & a few other of the old Dutch masters, who I find are only to be seen in Holland. I shall probably continue here a good portion of the winter" [Adapted from Hills, The Genre Painting of Eastman Johnson, pp. 40–41].
He made free copies after Rembrandt, Van Dyke, and the contemporary Belgian painter Louis Gallait. He stayed in the Netherlands until 1855 and developed a profitable career as a portrait painter. —PH
MacGibeny, 2021: See the linked image of Johnson's source, Portrait of Anna Wake (1605–before 1669) by Anthony van Dyck, 1628 (Mauritshuis, The Hague). The Van Dyck portrait was transferred to Mauritshuis in 1822, and thus would have been there when Johnson was working and visiting museums in The Hague, 1851–55. Note that Johnson chose to copy only the bust-length portion of the full-length portrait; he did the same with his portrait copy Alexander Hamilton (after John Trumbull), 1890.