 To the west of the nave is a small narthex, which is topped by an unusual rectangular tower. The tower was used either as a bell tower or watchtower, or possibly both. It was accessible via wooden ladders on the inside and the outside. It features four wide vaulted windows in its upper part and a rectangular dome covered with roof tiles. According to art historian Robert G. Ousterhout, the tower of the Church of the Holy Mother of God is the earliest example of a belfry integrated into a church building and arranged above the narthex in Balkan architecture. This design would later establish itself as standard in the Balkans. The construction of an integrated tower has been attributed to either Western European or oriental (Syriac or Armenian) influences.
