 Complete the following phrase:  At the outbreak of the Civil War in 1861, von Vegesack left for the United States and joined the Union Army. He became captain of the 58th Ohio Infantry. The same year, he was promoted to major in the staff of general John E. Wool. First he served in Fort Monroe. As an aide-de-camp ADC to Joseph K. Mansfield he took part in the artillery bombardment of Newport News. In 1862 he resigned, but then he joined Major General George B. McClellan in his siege of Yorktown. As an ADC to Butterfield he took part in the battles of 