According to the Bene Israel tradition, they arrived in India sometime in the first or second century when their ancestors were shipwrecked in western India while on a trading voyage to the far east. On the other hand, some historians have thought their ancestors may have belonged to one of the Lost Tribes of Israel, but the Bene Israel have never been officially recognized by Jewish authorities as such. After migrating to India the Bene Israel gradually assimilated to the people around them, while keeping some Jewish customs. The medieval Jewish philosopher Maimonides mentioned in a letter that there was a Jewish community living in India: he may have been referring to the Bene Israel.