The Kaifeng Jews are members of a small Jewish community in Kaifeng, in the Henan province of China who have assimilated into Chinese society while preserving some Jewish traditions and customs. Their origin and time of arrival in Kaifeng are a matter of debate among experts. Most scholars agree that a Jewish community has existed in Kaifeng since the Northern Song Dynasty (960–1127), though some date their arrival to the Tang Dynasty (618–907) or earlier. Kaifeng, then the capital of the Northern Song Dynasty, was a cosmopolitan city on a branch of the Silk Road. It is surmised that a small community of Jews, most likely from Persia or India, arrived either overland or by a sea route, and settled in the city, building a synagogue in 1163. It is difficult to estimate the number of Jews in China. Numbers may change simply because of a change in official attitudes. The last census revealed about 400 official Jews in Kaifeng, now estimated at some 100 families totalling approximately 500 people. Up to 1,000 residents have ties to Jewish ancestry, though only 40 to 50 individuals partake in Jewish activities.