Swabians become Suisse
Thurgau was first mentioned as a county in the duchy of Swabia in the 9th century. After the extinction of the counts of Kyburg in 1264, the Habsburgs inherited the rights. Medieval Thurgau was not yet a clearly defined historical region and included large parts of the present cantons of St. Gallen, Zurich and the German diocese of Constance. Constance was the religious and economic centre, and the people of Constance and Thurgau considered each other as Swabians.
The 15th century was decisive for the political development of Thurgau and by the end of the 15th century the term Swabians was only used for the northern part of Lake Constance. People south of Lake Constance were ‘(Kuh) Schweizer’ or Eidgenossen. These Alemanni were Swabians and became Swiss after1460 and 1499. (Source: Th. Maissen, Geschichte der Schweiz, Baden, 2015).