Kloster Muri
The first traces of human settlement around Aristau are scattered La Tène culture artifacts. The modern municipality of Aristau is made up of three separate sections or villages. The three sections that make up the municipality were first mentioned in 1153 as "Arnestowo, Althusern" and "Birchi". It was originally the seat of a vassal of the Lanzburg family. During the Late Middle Ages it was the possession of the lords of Baar and Muri Abbey. After 1285, the Abbey also owned the rights to hold courts and to collect tithes. In 1351 Catherine of Baar sold the rights and property in Aristau to Hartmann Heidegg. After the destruction of his tower in 1386 by troops from Lucerne and Zurich, the orchard at the foot of the tower was sold to the monastery of Hermetschwil. The remaining property was sold to Muri Abbey. The ruins of Werd Castle (of which no records exist) was possibly the home of the Lords of Aristau. In 1750 Aristau introduced a local tax. This tax led, in 1816, to the current community. However, the town councils of the three villages didn't unite until 1912.