His Royal Highness Crown Prince Alexander (1888-1934) at the military camp on the Banjica hill, Serbia (seated centre with sword on his knee) - Alexander was the nominal supreme commander of the Serbian army at the outbreak of WW1. The Serbian army distinguished itself in the battles at Cer and at the Drina (the Battle of Kolubara) in 1914, scoring victories against the invading Austro-Hungarian forces and evicting them from the country.