Tianzhu 天竺 is the ancient Chinese name for India that was used between the Later Han 後漢 (25-220 CE) and the Song 宋 (960-1279) periods. The term is a very crude transliteration of the word "Hindoo" or of the name of the River Indus. A somewhat older and less often-used, but phonetically more accurate term is Shendu 身毒 (read Yuandu), also written Xiandou 賢豆, Xindu 忻都, Xindusi 欣都思, Yindu 印都, Yindu 印毒, Xindi 信地, Xintou 辛頭, Xintou 新頭, or Xintao 新陶.
From the 4th century CE on the mercantile traffic between India and China was very intense, and while the Chinese mainly exported silk to India, the Indians sold to the Chinese spices, Buddhist paraphernalia and also cotton. The search for the roots of Buddhism and the authentic writings of Buddhism induced a lot of Chinese monks to travel to India. Chinese sources therefore provide a very detailed picture of India through the 1st millenium CE, often better than Indian sources do.