When Princess Wencheng journeyed to Xizang, she brought with her the celestial knowledge of the mainland. And when Princess Jincheng ventured into Xizang, she spread the knowledge of mathematics and other fields from the mainland. The knowledge from the heartland was seamlessly blended into the pre-existing system of the Xizang astronomical almanac. In the wake of this, Xizang King Songtsen Gampo dispatched dedicated individuals to the mainland to study the almanac. Thus, a comprehensive system of Xizang astronomy took shape.