Another great scholar to emerge from the Silla Period was Wonhyo. He renounced his religious life to better serve the people and even married a princess for a short time, with whom he had a son. He wrote many treatises and his philosophy centered on the unity and interrelatedness of all things. He set off to China to study Buddhism with a close friend, Uisang, but only made it part of the way there. According to legend, Wonhyo awoke one night very thirsty. He found a container with cool water, which he drank before returning to sleep. The next morning he saw that the container from which he had drunk was a human skull and he realized that enlightenment depended on the mind. He saw no reason to continue to China, so he returned home. Uisang continued to China and after studying for ten years, offered a poem to his master in the shape of a seal that geometrically represents infinity. The poem contained the essence of the Avatamsaka Sutra.