Aarwangen is a village and a municipality in the Oberaargau administrative district in the canton of Bern in Switzerland.HistoryAarwangen is first mentioned in 1255 as villa Arwangen.Aarwangen grew from a fortified toll crossing over the river Aare, in a region where there were few realistic crossing places. The first bridge was built in the early years of the 13th century, and by the 16th century this had developed into a covered wooden bridge and customs post, defended by a castle.During the 18th century, by road, and the 19th century, by rail, this became a busy and important trade route for the movement of goods between the western and eastern parts of Switzerland.The municipal coat of arms is black and silver. It represents the seal of the Aarwangen family, who built the first Aarwangen Castle on the southern riverbank, though the present structure only dates back to the Landvögte, or Bailiffs, of Bern in the 16th and 17th centuries. When the Aarwangen family died out in the year 1350 they were succeeded by, the closely allied Grünenberg family, both families being vassals of the Habsburg family. The Grünenberg family did not last long and had already disappeared from the archives by the early 14th century, when the city of Bern established sovereignty over the region. In 1432, after the conquest of the neighbouring Aargau, Aarwangen Castle was purchased by the city of Bern, which then acquired the remainder of the former Grünenberg estate, including the area of the current district of Aarwangen, in 1480.