Thun is a town and a municipality in the administrative district of Thun in the canton of Bern in Switzerland with about 43,783 inhabitants (around 90,000 in the agglomeration), as of 31 December 2013.
The area of what is now Thun was inhabited since the Neolithic age (mid-3rd millennium BC). During the early Bronze age there were a number of settlements along the lake shore and the Aare. A site at Renzenbühl had a local chief or nobleman’s grave which contained one of the richest collections of early Bronze Age artifacts in Europe. Another site at Wiler contained approximately 1,500 maritime snail shells which were harvested from the Mediterranean and traded over the Alps.
The name of the town derives from the Celtic term Dunum, meaning “fortified town”. It fell to Rome in 58 BC, when Roman legions conquered almost all of Switzerland, and it soon became one of the main centers of Roman administration in the region.
The Romans were driven out of Thun, and out of the rest of Switzerland, by the Burgundians around 400 AD. The Aare became the frontier between the Christian Burgundians and the Pagan, German-speaking Alemanni, who lived north. The region was mentioned for the first time during the 7th century, in the chronicle of Frankish monk Fredgar. The town is first mentioned in 1133 as Tuno.
The region of Thun became a part of the Roman Empire in 1033, when Conrad II gained the title of King of Burgundy. The emperors entrusted the Zäringhen family, centred in Bern, with subduing the unruly nobles of central Switzerland. Around 1190 Duke Zäringhen, built Thun castle and expanded the town. After Bertold’s death in 1218, his territories went to Ulrich III von Kyburg.
In 1264 Thun received town rights and in 1384 the town was bought by the canton of Bern. Thun was the capital of the Canton of Oberland of the Helvetic Republic, which lasted from 1798 until 1803.