The extent of Arab diffusion in the Orient in the first century BC, around 64 /63 BC, the year of Pompey's settlement in Syria, rendered by Arab groups who were moving from north to south then. Those were in the region centuries before the Romans, and migrated from south to north, from southern Arabia, north to Syria, including southern Anatolia, and parts of Mesopotamia. Such migrations took place at occasions, during the gradual destruction of the Ma'reb Dam in Yeman which took place before 447.