The Portrait of Dirck van Os is a later painting by Rembrandt (1606-1669), created circa 1658. It is currently in the permanent collection of the Joslyn Art Museum in Omaha, Nebraska. In 1898, the portrait was acquired by a New York art dealer from a private collector in St. Petersburg, Russia. In 1899, the portrait was sold to Boston businessman Frederick Sears. The painting was purchased by the Joslyn Museum in 1942 from a private collection. Initially believed to have been painted by Rembrandt himself, the painting was later reclassified as a painting from the "School of Rembrandt"; the likely work of one of Rembrandt's students. In the spring of 2012, under the guidance of Ernst van de Wetering, one of the world's foremost authorities on Rembrandt, the museum sent the painting to Amste