The first mention of the Armenian settlement in Bjni, in the Hrazdan River gorge, dates back to the 5th century. One can find the St. Blessed Virgin Church built in 1031. Under the Pahlavuni dynasty this church became a center where theology was taught and science developed. It was here that the works of Plato and Euclid were translated into Armenian. On an elevation not far from the church the walls of once-unassailable fortress are seen. Historians called Bjni an "unassailable cloister of Gods" since the fortress could be taken neither by a storm, nor by a long siege. The secret was that 3 underground ways connected the fortress to the neighboring settlements and provided the besieged with everything necessary for survival. One of those ways started at the St. Blessed Virgin Church.