The history of the Arabs begins in the mid-ninth century BC, which is the earliest known attestation of the Old Arabic language. The Arabs appear to have been under the vassalage of the Neo-Babylonian Empire; they went from the Arabian Peninsula to Mauritania. Original Arabic tribes originated in what is now Hejaz, Najd and Yemen and then spread to levant to establish what is known the Ghassanid and Lakhmid kingdoms, in which they began to appear in the southern Syrian Desert from the mid-third century AD onward, during the mid to later stages of the Roman and Sasanian empires. Tradition holds that Arabs descend from Ishmael, the son of Abraham. The Syrian Desert is the home of the first attested "Arab" groups, as well other Arab groups that spread in the land and existed for millennia.