It is not always clear whether they were originally Israelite in ancestry, genealogically Arab tribes that converted to Judaism, or a mixture of both. In Islamic tradition the Jewish tribes of the Hejaz were seen as the offspring of the ancient Israelites.[28]:4–5 According to Muslim sources, they spoke a language other than Arabic, which Al-Tabari claims was Persian. This implies they were connected to the major Jewish center in Babylon.[28]:5 Certain Jewish traditions records the existence of nomadic tribes such as the Rechabites that converted to Judaism in antiquity.