After a year's fighting in Brunete, Belchite and Teruel, the Brigade lost two senior officers, David Doran and Robert Hale Merriman at the Gandesa battle on the Aragon front. After which, in March 1938, Wolff became the battalion commander. He led the now Lincoln-Washington Battalion during the Battle of the Ebro and left Spain in November 1938 when the International Brigades were demobilized. Ernest Hemingway described him during this period: [he was] "...23 years old, tall as Lincoln, gaunt as Lincoln, and as brave and as good a soldier as any that commanded battalions at Gettysburg. He is alive and unhit by the same hazard that leaves one tall palm tree standing where a hurricane has passed."