Serbian defeat was considered to be imminent, at least by external onlookers, compared to the strength of the Austria-Hungary. Serbia had obviously prepared well, however, and after a series of battles in 1914–1915 (Battle of Cer, Battle of Kolubara), the loss and recapture of Belgrade, and a Serbian counter-offensive with occupation of some Austrian territories (in Syrmia and eastern Bosnia), the Austrian army backed off. On 5 July 1914, things changed as old King Peter I relinquished his duties to the heir apparent Alexander, making him his regent.