In 648, Tang Tai Zong wrote an article about Xuan Zang's west journey. He want to carve the article onto stone. He loved Wang Xizhi's calligraphy. However, Wang Xizhi had died hundreds years ago at that time. So he ordered Huai Ren to collect characters from existing Wang Xizhi's calligraphy works. At that time, there's still no computer. It's a huge project to collect all characters and put them together since they are not in same size. It took Huai Ren 25 years to finish this project. It's called Sheng Jiao Xu. Because Huai Ren is a good calligrapher himself, the collected art work is just like Wang Xizhi's originals.