Afghan Mr. Muscle, Kabul, Afghanistan

"Kábul has a castle celebrated for its strength, accessible only by one road. In it there are Musulmáns, and it has a town, in which are infidels from Hind."
—Istahkrí, 921
By the 11th century the Ghaznavids had finally made all of the remaining non-Muslim areas become fully Islamized, with the exception of the Kafiristan region. Afghanistan at that point became the center of many important empires such as the Tahirids, Saffarids, Samanids, Ghaznavids, Ghurids, and Timurids.
The region was overrun in 1219 by Genghis Khan and his Mongol barbarians, who devastated much of the land. His troops are said to have annihilated the ancient Khorasan cities of Herat and Balkh. The destruction caused by the Mongols depopulated major cities and caused much of the locals to revert to an agrarian rural society. Their rule continued with the Ilkhanate, and was extended further following the invasion of Timur who established the Timurid dynasty. The periods of the Ghaznavids, Ghurids, and Timurids are considered some of the most brilliant eras of Afghanistan's history as they produced fine Islamic architectural monuments as well as numerous scientific and literary works.