The Tang dynasty was one of the golden ages in Chinese history and presided over another period of Pax Sinica.[18] The Tang capital, Chang'an, was a major economic and cultural hub, and was the world's largest urban settlement at the time.[19] The Silk Road facilitated economic and cultural exchanges between China and the outside world, with Persians and Sogdians among those who benefited the most from such exchanges with China.[18] In the north, the First Turkic Khaganate was defeated and annexed;[20] in the west, the Tang dynasty extended its control as far as modern-day Afghanistan and the Aral Sea;[21][22] in the east, Tang control reached Sakhalin.[22] During its peak, the Tang dynasty maintained hegemony over 72 tributary states.[23] During this period, Chinese culture was revitalized and became more diverse and cosmopolitan.[18] The amount of interaction between China and Japan increased; Chinese influence on Japanese culture and politics became more prominent since the Tang dynasty.[24]