Early history
No archaeological evidence that indicates a settlement on the site of today?s city centre prior to the 12th century has been found so far. In antiquity, a Celtic oppidum stood on the �Engehalbinsel� north of Bern, fortified since the 2nd century BC (late La T�ne period), thought to be one of the twelve oppida of the Helvetii mentioned by Caesar. During the Roman era, there was a Gallo-roman vicus on the same site. The Bern zinc tablet has the name Brenodor "dwelling of Breno". In the Early Middle Ages, there was a settlement in B�mpliz, now a city district of Bern, some 4 km (2 mi) from the medieval city.
The medieval city is a foundation of the Z�hringer ruling family, which rose to power in Upper Burgundy in the 12th century. According to 14th century historiography (Cronica de Berno, 1309), Bern was founded in 1191 by Berthold V, Duke of Z�hringen.
In 1218, after Berthold died without an heir, Bern was made a free imperial city by the Goldene Handfeste of Holy Roman Emperor Frederick II.
Old Swiss Confederacy
In 1353 Bern joined the Swiss Confederacy, becoming one of the "eight cantons" of the formative period of 1353 to 1481. Bern invaded and conquered Aargau in 1415 and Vaud in 1536, as well as other smaller territories, thereby becoming the largest city-state north of the Alps, by the 18th century comprising most of what is today the canton of Bern and the canton of Vaud.
The city grew out towards the west of the boundaries of the peninsula formed by the River Aare. Initially, the Zytglogge tower marked the western boundary of the city from 1191 until 1256, when the K�figturm took over this role until 1345, which, in turn, was then succeeded by the Christoffelturm (located close to today's train station) until 1622. During the time of the Thirty Years' War two new fortifications, the so-called big and small Schanze (entrenchment), were built to protect the whole area of the peninsula
