in 627 in Arbon. In 720, a fortification on the site of the present castle was built by a Frankish troop. The foundations of this early fortress remain. The first written mention of Arbon is in "Itinerarium Antonini" of 771 where it is mentioned as in pago Arbonense. Arbon, along with most of the southern shore of Lake Constance belonged to Prince-Bishopric of Constance. In 1255, Bishop Eberhard von Waldburg gave Arbon a dispensation for market rights in the area and built the city wall. That century saw an influx of inhabitants from the surrounding farms. From 1262 to 1264, and again in 1266, the young duke of Swabia, Conradin of Hohenstaufen, resided in Arbon because the Bishop of Constance was his guardian. The surrounding towns of Steinach, Mörschwil, Horn, Goldach, Egnach, Roggwil, and Steinebrunn all belonged to the parish of Arbon. The 14th century saw further growth. Linen production and other crafts developed. Between 1322 and 1334, Bishop Rudolf von Montfort rebuilt the crumbling fortress. A fire of unknown cause in 1390 destroyed much of the Altstadt. A second fire in 1494 was set by the sons of a hanged thief. When Thurgau was conquered by the Swiss Eidgenossen in 1460, the Bishops of Constance retained Arbon. However, in the Swabian War of 1499, they lost civil rights over the territory, retaining only ecclesiastical supremacy. Arbon then became part of the Old Swiss Confederacy. The castle of Arbon in its present form was built in 1515 by Bishop Hugo von Hohenlandenberg. The tower is older and dates to 993. In 1525, the first stirrings of the Reformation reached Arbon. In 1537, the reformed congregation was forced to return the church of St. Martin to the Catholic Church and meet in the chapel in Erdhausen, although only a small minority of the population remained Catholic. Religious conflict continued until the 18th century. In 1712, Thurgau declared equality for the various faiths. In the 18th century, the linen and embroidery industry was established in Arbon. The industrialists built attractive villas in the area, such as the «Rotes Haus» built in 1750. In 1798, Thurgau was occupied by French troops, along with much of the rest of Switzerland. The adoption of the Swiss constitution ended Arbon's dependence on the Bishops of Constance. The Bishop's representative, Franz Xaver Wirz von Rudenz, was forced to leave the city. In 1803, Arbon became part of