Alexander Sahinian declared that Etchmiadzin holds a unique position in Armenian (and non-Armenian) architecture history because it reproduces features of different periods of Armenian architecture. According to Mack Chahin the cathedral's building is of "immense architectural interest, especially because of the many alterations and additions that have been made to it since its foundation. Thus, at the present day, the cathedral building incorporates more than one styles of architecture." Despite the fact that the cathedral was renovated many times through the centuries and some alterations were made in the 17th and 19th centuries, it retains the form of the building constructed in 483/4. The fifth-century building is the core of the cathedral, while the stone cupola, turrets, belfry, and rear extension are all later additions. Engraved on the exterior of the edifice are decorative geometric and floral patterns as well as blind arcades and medallions depicting saints. Portions of the northern and eastern walls of the original building have survived.