Oglethorpe then traveled to France, where both his sisters Anne and Fanny lived, he attended the military academy at Lompres, near Paris, where he met and befriended fellow-student James Francis Edward Keith. The following year, intending to fight in the Austro-Turkish War, he travelled to serve under military commander Prince Eugene of Savoy. With a letter of recommendation from the Duke of Argyle and several other prominent Britons, Oglethorpe and Louis François Crozat arrived and with Infante Manuel, Count of Ourém entered the Prince's service on 3 August as an aide-de-camp. Oglethorpe was present at the Battle of Petrovaradin in August 1716, although not actively engaged, at the Siege of Timisoara in September that same year he served as aide-de-camp. He found active command at the Siege of Belgrade, from 19 June to 16 August. After the death of his superior in combat, on 16 August, Oglethorpe as the most senior aide-de-camp acted ad adjutant general; as such he took possession of the Turkish camp, and reported to the Prince the casualty report. After the battle, he was offered the rank of lieutenant colonel in the army— which he never accepted.