Engineering features of Armenian medieval fortress construction and defensive systems

The geographical position of the Armenian Highlands and the constant state of warfare required the creation of special systems of defensive structures. In medieval Armenia and the Armenian Kingdom of Cilicia, a unique school of fortress construction developed, whose engineering and conceptual solutions allowed small forces to organize prolonged resistance against much larger armies. The first and most important principle of Armenian fortress construction was the maximum utilization of the natural defensive capabilities of the terrain. Fortresses were built on inaccessible cliffs, at the edges of gorges, or at the confluence of rivers, where natural chasms rendered access impossible from three sides. Walls were constructed only in those sections that were open or accessible to the enemy. Similar structures can be seen in Amberd, Baghaberd, Lambron, and other well-known fortresses located in geographically complex conditions. The technique of wall construction was also adapted to military requirements and the characteristics of the seismic zone. A technique called "midis" was used, where the outer and inner faces were lined with hewn massive stones (basalt, tuff), and the voids between them were filled with mortar and gravel. This structure provided the walls with exceptional flexibility during earthquakes and stability against the impacts of enemy siege machines. The walls were reinforced with semi-circular or rectangular towers that protruded from the line of the wall and all