The name of the rivalry sounds almost cinematic: The Great Game, or The Tournament of Shadows. But the implications were very serious: Britain feared a Russian takeover in Afghanistan would pave the way, almost literally, for an invasion of India. Russia, meanwhile, was extending its sphere of influence, as powerful countries tend to do. The Great Game ran for almost a century, from the start of 19th century to the start of the 20th, and ended with an imaginary border demarcating Afghanistan and Pakistan that ran right over ethnic tribal areas and has since given the U.S. fits.

On this day, November 21, in 1893, the Durand Line Agreement was signed by Sir Mortimer Durand, the foreign secretary of British India (now Pakistan) and the Afghan Amir Abdur Rahman Khan, establishing a buffer zone between the Russian and British spheres of influence.

The Pashtun tribesmen that live on both sides of the porous border have no interest in the Durand Line, moving from one side to the other as they have for centuries. The Pakistani ISI (Inter-Services Intelligence) meanwhile maintains very close ties to the largest tribes in Afghanistan, including the Taliban. Their close relationship was helpful when the U.S. armed Afghan mujahideen fighting against the Soviet invaders in the 1980s, but has since obviously become considerably more problematic.