Ikalto monastery was founded by Saint Zenon, one of the 13 Syrian Fathers, in the late 6th century. It was known as one of the most significant cultural-scholastic centres of Georgia. An academy was founded at the monastery during king David the Builder by Arsen Ikaltoeli (Ikaltoeli meaning from Ikalto) in the early 12th century. The Academy of Ikalto trained its students in theology, rhetoric, astronomy, philosophy, geography, geometry chanting but also more practical skills such as pottery making, metal work, viticulture and wine making and pharmacology. According to a legend the famous 12th century Georgian poet Shota Rustaveli studied there.
There are three churches on the monastery grounds – Khvtaeba, Kvelatsminda and Sameba. The main church, Khvtaeba (Holy Spirit), was built in the 8th–9th century on the site of an older church (in which Saint Zenon had been buried). In 1616 the Persian invaders led by Shah Abbas I set the Ikalto Academy on fire and it ceased to exist.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.