The northern apse is visible to the left, beyond the tower. The transept of the nave closes behind the West Tower.

Dominated by the cathedral, the city changed its appearance from the 10th century with the construction of St Maria im Kapitol, Gross St Martin (1150-1230), St Cäcilien (ca. 1130-1160; now part of Schnütgen-Mus) and St Aposteln (begun ca. 1030), which rose above the tightly packed burgher houses. One of the twelve Romanesque-era churches left in Cologne, which formed the shape of a cross within a circle in the city. Sancta Colonia was thus laid out according to the Christian plan of redemption by Archbishop Bruno I (953-965). St Aposteln is a three-aisled basilica with three apses (triconch choir, ca. 1200) and a small octagonal tower at the crossing.