大秦景教流行中国碑
In 1916 he published "The Nestorian Monument in China", an analysis of the Nestorian Stele, a monument describing the Chinese Nestorian church in 781 AD. The book summarised the competing theories about the stele. He also published a number of other books and articles on the relics of the Nestorians. His theories of religion were influenced by those of Max Müller.