Although in 1903 Prince Alexis announced that he was abandoning his claim to the throne he remained in Paris even after his cousin had ascended the throne, and in later years he would still claim that he should be king of Serbia saying in 1913 "I have no criticism to make of King Peter, except that I ought to be King of Serbia, as I am an eldest son." It was not until the outbreak of the First Balkan War that Prince Alexis came to Serbia. Determined to serve he received King Peter's permission and trimming his moustache to disguise his features enlisted into the Serbian Army as a private soldier. During the war he took part in the fighting at the Battle of Monastir and the Battle of Kumanovo.