Units of the Volunteer Corps earned distinction in the defense of eastern Romania, which postponed the Central Powers' advance during summer 1917. With the 11th Division, the Transylvanians-Bukovinians participated in the battles of Mărăști, Oituz and Mărășești. At the time, they were split between five regiments of the 11th Division: 2nd, 3rd Olt, 5th Chasseurs, 19th Caracal, 26th Rovine.