 The Patriarchal Cathedral of the Holy Ascension of God is not the first church building to occupy the position on top of the Tsarevets hill . It was constructed directly on top of a late Roman ( early Byzantine ) basilica which dates to the 5th – 6th century AD . The Roman basilica may have remained in use by the local congregation during the First Bulgarian Empire , though it was no longer active by the time the construction of the current church began . 
