ABSTRACT
Born in the Gaozong reign in the Tang Dynasty, Gautama Siddhartha was an Indian Buddhist. Although he was an Indian Buddhist, he is not to be confused with the historical Buddha, whose name was also Gautama Siddhartha. During the Tang Dynasty, three families of Indian Buddhist astronomers served in the Tang court: the Gautama family, the Kasyapa family, and the Kumara family. The Gautama family served the longest period at the Imperial Bureau of Astronomy, and during the Kaiyuan and Tianbao reign periods, the position was actually called 'Gautama Directorate'. Gautama Siddhartha served as the Director of Astrology in the Tang court from 711 to 718 CE. He translated the Navagraha Calendar by imperial command. The title of this calendar, Jiuzhi refers to the sun, moon and five planets, plus the two invisible planets Rahu and Ketu.
