Uspenskiy (St. Dormition) Cathedral (1156-1160) is the oldest church in Volyn (the only church preserved from the period before the Mongol invasion). It was erected in the 12th century by the Prince Mstyslav Iziaslavych, great-grandson of Volodymyr Monomakh. Sometimes it is called Mstyslav’s Church. For the whole centuries the cathedral was used as a graveyard for Galytsko-Volyn Princes, such as Prince Mstyslav Iziaslavych, the founder of church, Princes Vasylko Romanovych and Volodymyr Vasylkovych (accordingly, brother and nephew of King Danylo Galytskyi). The noble person and priests of Volyn are also buried therein. St. Dormition Cathedral was used not only as the main church of Volyn but also as an epicenter of culture and education. There was a parishioners’ school and the artists’ workshop. It served as a venue for making inter-state treaties and the Parties swore in the Gospel in order to comply with them. Princes got crowned and married in the cathedral. As stated in Galytskyi-Volyn Chronicles,the Lithuanian Prince Dmytro Bobok married Ann, a daughter of the Moscow Prince Ivan Krasnyi (John the Red) in that church in the 14th century. Later Dmytro was famous for a hero of the Battle of Kulikovo Field. During the Mongol and Tatar Invasion (1241) the strong walls of Uspenskiy Cathedral were the last shelter for the citizens and defenders. As stated in chronicles, when the Orda left Volodymyr nobody survived and the church was full of corpses.
In early 17th century the Bishop Ipatius Potius lived in the cathedral. He was one of the initiators of Brest Union (1596) and one of the founders of Greek Catholic Church. The cathedral was decorated by the Italian masters. The complex of cathedral includes also the entrance gate (the 17th century), the Bishop’s Palace (the 15th century) and the bell tower (the 15th century).
In the church graveyard there is a grave of Omelian Dvernytskyi (1834-1906), a nobleman, a judge and a historian. He used all his best to restore the Mstyslav’s Church in late 19th century. He was buried in the church graveyard for such a great merit to the church and to citizens.