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 Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.