easy question to give a speculative answer, namely, they were given Canaan by the king of Babylon
in ancient times, kings & queens were also 'gods'
the 'god' that promised Abraham Canaan was obviously the ruler of Babylon
when the Jews were naughty, the ruler of Babylon booted them out, since it was simply 'borrowed land'
the Jews have spent their entire history as opportunistic wanderers, from Chaldea, to Canaan, to Egypt, around Roman Empire, like St Paul (Saul) lived not in Israel, Spain, Europe, etc
thus this was probably always known by powers, such as the Romans, that the Jews were just opportunistic wanderers
