In prehistoric times (
Neolithic), the lands of the canton were inhabited by people of the
Pfyn culture, named after
Pfyn, along
Lake Constance. During
Roman times the canton was part of the province
Raetia until 450, when the
Alemanni settled on the lands. Roman settlements in Thurgau include Ad Fines (Pfyn),
Arbor Felix and
Tasgetium. In the sixth century,
Thurgovia became a
Gau of
Francia as part of
Alamannia, passing to the
Duchy of Swabia in the early 10th century. At this time,
Thurgovia included not just what is now the canton of Thurgau, but also much of the territory of the modern
canton of St. Gallen, the
Appenzell and the eastern parts of the
canton of Zurich. The most important cities of Thurgovia in the
early medieval period were
Konstanz, as the seat of the bishop, and
St. Gallen for the
Abbey of Saint Gall. The dukes of the
House of Zähringen and the counts of the
Kyburg family took over much of the land in the
High Middle Ages. The town of
Zurich was part of the Thurgau until it became
reichsunmittelbar in 1218. When the Kyburg dynasty became extinct in 1264, the
House of Habsburg took over that land. The
Old Swiss Confederacy, allied with ten freed
bailiwicks of the former
Toggenburg, seized the lands of the Thurgau from the Habsburgs in 1460, and it became a subject territory of seven Swiss cantons (Zurich, Lucerne, Uri, Schwyz, Unterwalden, Zug and Glarus). During the Protestant
Reformation in Switzerland, both the Catholic and emerging Reformed parties sought to swing the subject territories, such as the Thurgau, to their side. In 1524, in an incident that resonated across Switzerland, local peasants occupied the cloister of
Ittingen in Thurgau, driving out monks, destroying documents, and devastating the wine-cellar. Between 1526 and 1531, most of the Thurgau's population adopted the new Reformed faith spreading from Zurich; Zurich's defeat in the 1531
Second War of Kappel ended Reformed predominance. Instead, the First Peace of Kappel protected both Catholic and
Reformed worship, though the provisions of the treaty generally favored the Catholics, who also made up a majority among the seven ruling cantons. Religious tensions over the Thurgau were an important background to the
First War of Villmergen (1656), during which Zurich briefly occupied the Thurgau. In 1798, the land became a canton for the first time as part of the
Helvetic Republic. In 1803, as part of the
Act of Mediation, the canton of Thurgau became a member of the Swiss confederation. The
cantonal coat of arms was designed in 1803, based on the coat of arms of the Kyburg family, which ruled the Thurgau in the 13th century, changing the background to green-and-white, at the time considered "revolutionary" colours (cf.
tricolour); as the placement of a yellow (
or) charge on white (
argent) is a violation of heraldic principles, there have been suggestions to modify the design, including a 1938 suggestion to use a solid green field divided by a diagonal white line, but they were unsuccessful. On March 26, 1806, Thurgau became the first state in the world to introduce compulsory
smallpox vaccinations, by order of the cantonal councillor
Jakob Christoph Scherb. The current cantonal constitution of Thurgau dates from 1987. ==Geography==