Complex sentence: In 653, when its location became known, Catholicos Nerses III the Builder built the Church of Surb Nshan (Holy Seal), described by Robert H. Hewsen as "a simple hermitage".
Split into simpler sentences: In 653, when the location was discovered, Catholicos Nerses III the Builder built the Church of Surb Nshan (Holy Seal). It is described by Robert H. Hewsen as "a simple hermitage".