The Tang dynasty established a second Pax Sinica, and the Silk Road reached its golden age, whereby Persian and Sogdian merchants benefited from the commerce between East and West. At the same time, the Chinese empire welcomed foreign cultures, making it very cosmopolitan in its urban centres. In addition to the land route, the Tang dynasty also developed the maritime Silk Route. Chinese envoys had been sailing through the Indian Ocean to India since perhaps the 2nd century BCE, yet it was during the Tang dynasty that a strong Chinese maritime presence could be found in the Persian Gulf and Red Sea into Persia, Mesopotamia (sailing up the Euphrates River in modern-day Iraq), Arabia, Egypt, Aksum (Ethiopia), and Somalia in the Horn of Africa.