Klosterkirche St. Marien und St. Cyprian, Medieval monastery church in Nienburg, Germany.

Klosterkirche St. Marien und St. Cyprian is a medieval monastery church in Nienburg an der Saale in Saxony-Anhalt. The building combines Gothic architecture with earlier Romanesque elements, particularly visible in the southern choir wall and window frames.

The Benedictine monastery was founded at Thankmarsfelde in 970 and moved to Nienburg in 975; the church was consecrated in 1004 and burned down in 1042. Its successor, built 1042–1060 with support from Emperor Henry III, was destroyed by fire in 1242, after which the crypt was abandoned and the choir level lowered. A further fire in 1280 preceded the three-aisled hall church, the earliest Gothic hall in eastern central Germany.

A sandstone column inside displays the agricultural work of each month, linking the religious space with the daily tasks of medieval rural workers. This connection shows how the church reflected the rhythms of village life in earlier times.

To visit the interior, you should arrange this in advance with the parish office since the church is still actively used by the community. Contacting ahead ensures you can see it at a convenient time for both you and the church.

In the western bay of the south aisle lie fragments of a late Romanesque stucco floor, found above the crypt of the earlier building. Too little survives to reconstruct the original pattern, so the pieces are shown as found rather than restored.