The Ddmashen Surb Tadevos (St. Thaddeus) church is located in the eastern part of the village of Ddmashen, Gegharkunik province. It is an early medieval, domed-hall type church. According to the research of architect Areg Hasratyan, the structure is dated to the middle of the 7th century.
The church is built of cleanly dressed, yellowish-red tufa stones and rises on a multi-stepped foundation. Its exterior dimensions are about 12.8 × 22.5 m. In size it is smaller than the similarly typed monuments of Aruch and Ptghni.
The village, abandoned in the late medieval period, was resettled in 1828 by refugees from Maku, who renovated the church and covered its ruined dome and roof with wood; in 1907 they built a new dome and restored the roof in stone.
The side chambers on either side of the semicircular main apse have small apses of their own and are covered with barrel vaults. The church has two doors, from the south and the west.
On the lintel of the church's western entrance, a single-line, unfinished inscription has survived. The stone probably cracked down the middle while it was being carved. The decoration of Ddmashen's St. Thaddeus church is restrained.
