The Great Saint Martin Church is a Romanesque Catholic church in Cologne, Germany. Its foundations rest on remnants of a Roman chapel, built on what was then an island in the Rhine. The church was later transformed into a Benedictine monastery. The current buildings, including a soaring crossing tower that is a landmark of Cologne's Old Town, were erected between 1150-1250. The architecture of its eastern end forms a triconch or trefoil plan, consisting of three apses around the crossing, similar to that at St. Maria im Kapitol. The church was badly damaged in World War II; restoration work was completed in 1985.
As of 2009 Great Saint Martin is being used by a branch of the Monastic Fraternities of Jerusalem and is open for visits again.