In July 1951 a large antique building was found under the former Detmag store located in Saborna Street. This building is parallel with the St George Church ensemble and is just 11 meters south from it. The Serdica's eastern walls are 6 meters away from this building. These 6 meters ate supposed to be a street. Three of the corners of the building are still not excavated they remain buried under Saborna st. and Tzar Kaloyan st.
It is an interesting fact that in the west part of this building at the depth of 3.60 meters are found remains of a street. That proves the building was built in later period of time over the antique street. The street had passed east form saint George Church. The construction methodology of the building - mixed masonry with 4 layers of bricks is typical for IV century.