Outside the Zhonghua Gate of Nanjing, opposite to the Grand Bao’en Temple Heritage and Scenic Area, there is a historical bathhouse, a domed structure known as Wengtang (Vase Hall). According to historical literature, the bathhouse was built and attached to the Bao’en Temple in the early Ming dynasty. Based on data obtained through 3D laserscanning of the building, this article analyses the characteristics of its layout and form. Through comparison with Islamic bathhouses, the article suggests that this kind of domed structure was introduced to China from Central and West Asia in the Yuan dynasty and bloomed in the Chinese Jiangnan area in the Ming and Qing dynasties. Therefore, the Nanjing bathhouse bears witness to the lively exchange of architectural ideas among regions in Asia during the thirteenth and fourteenth centuries.