 Most importantly for Chinese art history, the Wei rulers converted to Buddhism and became great patrons of Buddhist arts.Many of the most important heritages of China, such as the Yungang Grottoes, the Longmen Caves, the Shaolin Monastery, the Songyue Pagoda, were built by the Northern Wei.Important books such as Qimin Yaoshu and Commentary on the Water Classic, a monumental work on China's geography, was written during the era.