[6] The abbey is said to have been built at the site of the hermitage of Irish missionary Gallus, who according to legend had established himself by the river Steinach in AD 612.

[6] The abbey prospered in the 9th century and became a site of pilgrimage and a center of trade, with associated guest houses, stables and other facilities, a hospital, one of the first monastery schools north of the Alps.

Saint Wiborada, the first woman formally canonized by the Vatican,[8] reportedly saw a vision of the impending attack and warned the monks and citizens to flee.

[3] In 1207, Abbot Ulrich von Sax was granted the rank of Imperial Prince (Reichsfürst) by Philip of Swabia, King of the Germans.

[6][7] As an ecclesiastical principality, the Abbey of St. Gallen was to constitute an important territorial state and a major regional power in northern Switzerland.

Ulrich entered public affairs in the early 1460s and attained the various offices and honours that are available to a talented and ambitious man.

According to Vadian, who understood his contemporaries well, "Ulrich was a very intelligent, observant, and eloquent man who enjoyed the trust of the citizenry to a high degree."

When he arranged for the help of the Pope and the Emperor to carry out a plan to move the abbey to Rorschach on Lake Constance, he encountered stiff resistance from the St. Gallen citizenry, other clerics, and the Appenzell nobility in the Rhine Valley, who were concerned for their holdings.

For this purpose he established contact with farmers and Appenzell residents (led by the fanatical Hermann Schwendiner) who were seeking an opportunity to weaken the abbot.

Initially, he protested to the abbot and the representatives of the four sponsoring Confederate cantons (Zürich, Lucerne, Schwyz, and Glarus) against the construction of the new abbey in Rorschach.

Then on 28 July 1489 he had armed troops from St. Gallen and Appenzell destroy the buildings already under construction, an attack known as the Rorschacher Klosterbruch.

He was confident that the four sponsoring cantons would not intervene with force, due to the prevailing tensions between the Confederation and the Swabian League.

The people of Appenzell and the local clerics submitted to this force without significant resistance, while the city of St. Gallen braced itself for a fight to the finish.

Ulrich, overwhelmed by the responsibility for his political decisions, panicked in the face of the approaching enemy who wanted him apprehended.

However, other political ramifications resulted from the court action, because the Confederation gained ownership of the city of St. Gallen and rejected the inroads of the empire.

On the other hand, the matter deepened the alienation between Switzerland and the German Holy Roman Empire, which eventually led to a total separation after the Swabian War.

Starting in 1526 then-mayor and humanist Joachim von Watt (Vadian) introduced the Protestant Reformation into St. Gallen.

The first depression occurred in the middle of the 18th century, caused by strong foreign competition and reforms in methods of cotton production.

The city lies between Lake Constance and the mountains of the Appenzell Alps (with the Säntis as the highest peak at 2,502 meters (8,209 ft)).

[14] St. Gallen has a humid continental climate (Dfb) with short, warm summers and long, moderately cold winters.

While the daily average level of gamma-ray radioactivity in the city is unremarkable at 105 nSv/h, the maximum can reach 195 nSv/h, as high as the average for Jungfraujoch, the location with the highest reported level of radioactivity in Switzerland, due to its high elevation and therefore greater exposure to cosmic rays.

The same report explains that the unusually high spikes of radioactivity measured in St. Gallen are due to radioactive products of radon gas being washed to the ground during heavy storms, but does not explain where the sufficient quantities of radon gas and its products to account for the anomaly would come from.

[23] The last regular election of the City Parliament was held on 27 September 2020 for the mandate period (German: Legislatur) from January 2021 to December 2024.

[39] It is comparatively small, with about 6,500 students enrolled at present, has both EQUIS and AACSB accreditations, and is a member of CEMS (Community of European Management Schools).

The St. Gallen Symposium is the leading student-run economic conference of its kind worldwide and aims to foster the dialogue between generations.

[41] In addition to the state system, St. Gallen is home to the Institut auf dem Rosenberg — an élite boarding school attracting students from all over the world.

[42] The canton's Gewerbliches Berufs- und Weiterbildungszentrum is the largest occupational school in Switzerland with over 10,000 students and various specialty institutes.

In 1992, St. Gallen was awarded the Wakker Prize for the city's effort to create a unified structure and appearance in current and future construction.

[44] There are 28 sites in St. Gallen that are listed as Swiss heritage sites of national significance, including four religious buildings; the Abbey of St. Gallen, the former Dominican Abbey of St. Katharina, the Reformed Church of St. Laurenzenkirche and the Roman Catholic parish church of St. Maria Neudorf.

The "St. Gallen 2013" project aimed to improve local rail services, with infrastructure upgrades and new rolling stock.