Fortified Church of St. Arbogast, Romanesque fortified church in Muttenz, Switzerland

The Fortified Church of St. Arbogast stands in the Oberdorf of Muttenz, its free-standing nave, raised Romanesque choir and altar house joined by a tower on the north side. A roughly seven-metre-high ring wall with battlements and two gate towers, north and south, encloses the churchyard; the guard house and the sexton's house lean against the outside of the wall.

Alemannic settlers built a wooden church in the 5th century on the foundations of an abandoned Roman building; a stone church followed in the 8th or 9th century and was replaced around 1000. After the Basel earthquake of 1356 brought down the north wall and vault, Konrad Münch-Löwenberg began rebuilding in 1359, and around 1420 Hans Thüring Münch-Eptingen raised the tower and enclosed the churchyard with a wall as a refuge for the village.

The church keeps its late-Gothic carved wooden ceiling by Ulrich Bruder from 1504 and a baptismal font dated 1618. Wall paintings of the Arbogast and Nicholas legends, found during the 1880 renovation, were plastered over again; only the Last Judgement stayed visible until all were uncovered in 1973–1975. The parish still belongs to the Evangelical-Reformed Church of Basel-Landschaft.

The church stands in the Oberdorf of Muttenz, at the centre of the old village between the Rütihard and Wartenberg hills. The ring wall is pierced by two gate towers, north and south; the 17th-century guard house adjoins the north tower and the 1553 sexton's house the south tower. The church is still used by the local Reformed parish.

This building is the only church in Switzerland completely surrounded by defensive walls. This extraordinary fortification was necessary to protect the community during the uncertain times of the medieval period.