Mandelsloh is an ancient settlement and it has had a church for many centuries. The present church was built in 1175-90 as a cross-shaped basilica with a low timber ceiling. The tower, made of ironstone, was added in the 15th century.

Among the impressive wall paintings inside there is one from 1425 which shows St. Osdag to whom the church was consecrated. The knight with the cudgel in his hand was the Duke of Burgundy and legend tells that he was slain in the battle against the Norsemen at Ebstorf in 880. His sister took his body to Mandesloh where they made him a local saint.

Out of many old churches in the region of Neustadt the St. Osdag church in Mandelsloh is particularly special. The roman basilika has been the first monumental brick construction in northern Germany. Besides the ornamental paintings of the ceiling there are gems of medieval wall paintings on the choir wall. To the web site of Mandelsloh.