In the 19th century, Afghanistan was a buffer state in 'the Great Game' between the British and Russian Empires. The area was thought unconquerable despite being the source of many empires, and many empires having a go due to its strategic positioning on the silk road. Arab Muslims brought Islam to the area in the 7th century, but the locals had been influenced by Buddhists, Zoroastrians, Jews and others. In 1219, Genghis Kahn's empire swallowed the area. There were three Anglo-Afghan wars (1839-42; 1878-80 and 1919), but Britain eventually gave up, and there was increasing influence from Soviet Russia. In 1978, the communist PDPA Party seized power and the area entered the Cold War. 65 countries boycotted the 1980 Moscow Olympics because of the Soviet War in Afghanistan (1979-1989). Some argue that it was this war that sapped the last strength from the USSR, brought down the wall in Berlin, and freed Nelson Mandela.