Traditional German historiography counts six "Altstämme" or "ancient stems", viz. Bavarians, Swabians (Alamanni), Franks, Saxons, Frisians and Thuringians. All of these were incorporated in the Carolingian Empire by the late 8th century. Only four of them are represented in the later stem duchies; the former Merovingian duchy of Thuringia was absorbed into Saxony in 908 while the former Frisian kingdom had been conquered into Francia already in 734. The customary or tribal laws of these groups were recorded in the early medieval period ("Lex Baiuvariorum", "Lex Alamannorum", "Lex Salica" and "Lex Ripuaria", "Lex Saxonum", "Lex Frisionum" and "Lex Thuringorum"). Franconian, Saxon and Swabian law remained in force and competed with imperial law well into the 13th century.