Around 700 ad, the Chinese princess Wencheng, who married the king of Tubo (old name for Tibet), Songsan Gampo, brought Buddhism into Tibet.
She also took the gilt statue of Buddha at age of 12 with her, which is one of the most precious treasure in Buddhism.
Gampo built the Potala palace for the arrival of the princess. After the wedding, they worked together to build a holy temple in Lhasa.
But many times they tried, floods always came and destroyed the new temple.
Therefore princess Wencheng looked at the shape of Lhasa, and found it was like a lying female devil. It was a small lake which lied at the position of her heart.
So she ordered that the lake should be filled with earth, and on this position a temple should be built. This temple was never destroyed by flood.
After many years, another Chinese princess who married the king of Tubo, ordered to move the statue of Buddha brought by Wencheng into this temple.
This temple is the Jokhang.