In the Church of Saints Peter and Paul the relics of St. John of Polivotsky were transferred to the church by Tsar Kaloyan in the capital city of Turnovo in 1204. Subsequently, a monastery complex was formed around the church. It was built according to the will and priesthood of Anna-Maria (1221–1237), wife of Tsar Ivan Assen II. During the Ottoman rule, hundreds of manuscripts from the royal library were placed there. Many of them were destroyed in 1842 by the Greek ruler.
The church is dedicated to the Christian Apostles Saint Peter and Saint Paul. It follows the cross-domed design and has a single apse. The cella is divided into three naves by two rows of columns. The columns' capitals are decorated with plastic carving and tracery. The church has a high, massive iconostasis. According to the 14th-century account of Patriarch Evtimiy, the church and the surrounding monastery were built on the order of Tsar Ivan Asen II's (ruled 1218–1241) wife Anna.
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.