The Holy Trinity Cathedral is the oldest church in Ruse and the most important for the Ruse Metropolis.

The church was built in 1632. The church is dug four and a half meters below the level of the courtyard according to the height requirements for Christian churches during Ottoman rule. So at first glance, the church seems small, but when you enter inside, you can see how tall and spacious it is. The current appearance of the church dates back to the time after the Liberation. It is a three-aisled pseudo-basilica with external dimensions of 15.60 x 31.20 meters.

You go down to the church by stone steps, and above them is a beautiful dome built in the Russian style. The bell tower is the highest part of the church - 19 meters. The walls were painted in 1934 in a style resembling Russian icon painting. Two chapels were built through donations. One is dedicated to "St. Alexander Nevsky" and was consecrated in 1884. It was rebuilt in 1983, and a museum exhibition of church utensils, icons, and old printed books was placed in it. The second chapel is dedicated to "St. St. Cyril and Methodius". It was consecrated in 1886. In 2000, stained glass windows were installed on the temple windows.