The basilica of St. Ludgerus has its origins around 800 A.D. This was when the Frisian missionary Liudger, who became the first Bishop of Münster, founded a Benedictine monastery here. The abbey church was constructed in 1256 in the architectural style that still exists today. It is especially note worthy as it is one of the last testimonies to the Romanesque architectural period in the Rhineland area with its cruciform, three naves galleried Basilica.

The precious monastery treasures of this ruling imperial abbey were mostly spared of fires and pillages; however a large part of the treasures were vandalized during the secularisation of 1802/1803. This is why the important Werdener manuscripts of the monastery library can only be seen today as facsimiles. The treasure rooms have been preserved including a late Antic period ivory pyxis, a Franconian relic box and the 9thcentury Liudger-Chalice.