In 1915, he was sent to the Eastern Front as a non-commissioned officer and took part in the Battle of Warsaw. He contracted jaundice and pneumonia, and had to be evacuated to a hospital on the Baltic Sea. While recuperating, he received a letter from his girlfriend Lucie Mannheim, telling him that she had found work at the Front Theatre in Libau. Intrigued, Veidt applied for the theatre as well. As his condition had not improved, the army allowed him to join the theatre so that he could entertain the troops. While performing at the theatre, his relationship with Mannheim ended. In late 1916, he was re-examined by the Army and deemed unfit for service; he was given a full discharge on 10 January 1917. Veidt returned to Berlin where he was readmitted to the Deutsches Theater. There, he played a small part as a priest that got him his first rave review, the reviewer hoping that "God would keep Veidt from the films." or "God save him from the cinema!"