"The Alemanni (also Alamanni; Suebi "Swabians") were a confederation of Germanic tribes on the Upper Rhine River. First mentioned by Cassius Dio in the context of ...
the campaign of Caracalla of 213, the Alemanni captured the Agri Decumates in 260, and later expanded into present-day Alsace, and northern Switzerland, leading to the establishment of the Old High German language in those regions, by the eighth century named Alamannia.
In 496, the Alemanni were conquered by Frankish leader Clovis and incorporated into his dominions. Mentioned as still pagan allies of the Christian Franks, the Alemanni were gradually Christianized during the seventh century. The Lex Alamannorum is a record of their customary law during this period. Until the eighth century, Frankish suzerainty over Alemannia was mostly nominal. After an uprising by Theudebald, Duke of Alamannia, though, Carloman executed the Alamannic nobility and installed Frankish dukes. " - (en.wikipedia.org 10.08.2021)