Political map of South & Southwest Asia 14 September 1915 (Niedermayer-Hentig Expedition): Even as the Allies were landing at Gallipoli (Gallipoli Campaign), a German expedition was preparing to depart Constantinople for Kabul (Niedermayer–Hentig Expedition) with the intention of persuading Afghanistan to invade British India. Britain responded with a cordon in eastern Persia (Seistan Force), but failed to stop the Germans getting through. Although the Afghan Emir ultimately rejected the German advances, the mission undermined British prestige in the region.