The origins of Kaifeng's Jewish community are something of a mystery. A Song-dynasty stele now in the town museum records that they arrived here in the Zhou dynasty, nearly three thousand years ago, though this seems doubtful. It's more likely their ancestors came here from central Asia around 1000 AD, when trade links between the two areas were strong, a supposition given some weight by the characteristics they share with Persian Jews, such as their use of 27 rather than 22 letters of the Hebrew alphabet. The community was never large, but it seems to have flourished until the nineteenth century, when perhaps as a result of disastrous floods, including one in 1850 which destroyed the synagogue, the Kaifeng Jews almost completely died out. The synagogue, which stood at the corner of Pingdeng Jie and Beixing Jie, on the site of what is now a hospital, was never rebuilt, and no trace of it remains today. A number of families in Kaifeng trace their lineage back to the Jews, and, following the atmosphere of greater religious tolerance in contemporary China, have begun practising again. You can see a few relics from the synagogue in Kaifeng Museum, including three steles that once stood outside it, but most, such as a Torah in Chinese now in the British Museum, are in collections abroad.