Although the vicissitudes of the Ottoman Empire during World War I are well known, the fate of Iran during the same period remains relatively unappreciated. Officially neutral in the conflict, Iran in fact found itself overrun and occupied by various foreign powers. Following a 1907 accord with Britain that divided the country into two spheres of influence, Iran by 1911 found much of its northern half practically occupied by Russia. Intent on safeguarding its Indian possessions, Britain, meanwhile, controlled most of the south. With the outbreak of the Great War, these traditional rivals were joined by the Ottomans, who, supported by local tribes and Iranian nationalists loath to see half of the country controlled by Russians, invaded Azerbaijan in early 1915. Finally, there were the Germans, who, supported by an alliance with the Ottomans, infiltrated Iran later in 1915 as part of a grand strategy designed to destabilize the country by inciting its population against the British and eventually to forge a German–Iranian alliance.