at the time of its first historical mention, the area of the lahngau lay in the settlement area of a germanic tribe called the ubii. after the migration of ubii across the rhine ca. 39 bc, the area was rather sparsely populated. it evolved into a border region between the franks in the westerwald, the chatti in present-day north hesse, and the alamanni in the taunus and wetterau. in the 5th and 6th centuries, the franks gained the supremacy. the chatti became members of the frankish tribal confederation, and alamannia became a frankish protectorate. this enabled the franks to incorporate the territory of the lahngau into its empire. during the period of frankish conquest, the frankish conradine family established itself as a leading noble house in the lahngau. the conradines maintained close familial relationships with the carolingians and robertians.