The "Tang Annals" say that the Tibetan emperor Songtsen Gampo conquered and unified the Zhangzhung. In 634, Yangtong (Zhang Zhung) and various Qiang tribes, "altogether submitted to him." Gampo then united the Yangtong to defeat the 'Azha or Tuyuhun and conquer two more Qiang tribes. He then threatened Songzhou (China) with an army of more than 200,000 men. He then sent gifts of gold and silk to the Tang emperor to marry a princess. At first the Emperor Gaozong of Tang refused so Gampo attacked Songzhou. But Gampo later gave up and apologized so the emperor married him to Princess Wencheng.