St Michael's Church was built between 1010 and 1020 on a symmetrical plan with two apses that was characteristic of Ottonian Romanesque art in Old Saxony. Its interior, in particular the wooden ceiling and painted stucco-work, its famous bronze doors and the Bernward bronze column, are – together with the treasures of St Mary's Cathedral – of exceptional interest as examples of the Romanesque churches of the Holy Roman Empire.
St Michael's Church has exerted great influence on developments in architecture. The complex bears exceptional testimony to a civilization that has disappeared. These two edifices and their artistic treasures give a better overall and more immediate understanding than any other decoration in Romanesque churches in the Christian West.
The ancient Benedictine abbey church of St Michael, built between 1010 and 1022 by Bernward, Bishop of Hildesheim, is one of the key monuments of medieval art. Of basilical layout with opposed apses, the church is characterized by its symmetrical design: the east and west choirs are each preceded by a transept which protrudes substantially from the side aisles; elegant circular turrets on the axis of the gable of both transept arms contrast with the silhouettes of the massive lantern towers located at the crossing. In the nave, the presence of square impost pillars alternating in a original rhythm with columns having cubic capitals creates a type of elevation which was prove very successful in Ottonian and Romanesque art.
St Mary's Cathedral, rebuilt after the fire of 1046, still retains its original crypt. The nave arrangement, with the familiar alternation of two consecutive columns for every pillar, was modelled after that of St Michael's, but its proportions are more slender.
The church of St Michael and the cathedral contain an exceptional series of elements of interior decoration that together are quite unique for the understanding of layouts used during the Romanesque era. First come the bronze doors dating to 1015, which retrace the events from the book of Genesis and the life of Christ, and the bronze column dating from around 1020, the spiral decor of which, inspired by Trajan's Column, depicts scenes from the New Testament.
These two exceptional castings, the first of this size since antiquity, were commissioned by Bishop Bernward for St Michael's; they are now preserved in the cathedral. Also of special significance are the corona of light of Bishop Hezilon and the baptismal fonts of gold-plated bronze of Bishop Conrad.