Battle of Galicia
At the beginning World War I Ernstberger was sent to the Eastern Front and a member of a Kaiserjäger (mountain infantry) unit and participated in the Battle of Galicia. In 1917 he was made the leader of a group building monuments of fallen soldiers ("Denkmal-Bauabteilung"). He designed a monument of mountain infantry in Bolzano, their museum in Runkelstein Castle in what was Austro-Hungarian Tyrol and their monument and cemetery in Huijcze Galicia.