A unique feature in the church is the stucco decoration in the sanctuary (haikal). It is part of the total rebuilding of this part of the building by Moses of Nisibis (early 10th century). The decoration has a purely ornamental character, consisting of stylised floral patterns.
In the annex chapel of the 49 Martyrs a similar kind of stucco has been made on the eastern wall of the sanctuary. The only parallel for it in Egypt can be found in the mosque of Ibn Tulun in Cairo, finished in 884. These stuccos were the work of craftsmen from Samarra and it is very likely that Moses brought the craftsmen who made the decoration of the sanctuary from the same region. Tikrit, the town in Iraq from where many of the monks in Deir al-Surian originated, lies just north of Samarra.
