The basilica was built in the 16th century and is the oldest and only underground church in Vratsa. There are very few preserved underground faith houses in Bulgaria. It is named St. Nicholas and is located in the yard of the Metropolitan Temple of the same name, near June 2nd Boulevard.
Built according to an Ottoman requirement for Christian temples to be within the height of a horse-mounted Turk, it was dug six meters underground and measured 7 m along and 3.80 m across. Historical evidence indicates that its patron was Boyar Georgi, whose daughter was married to a Turkish dignitary in Constantinople. Legend has it that the pretty girl was taken by force and asked her father to build this chapel to obtain forgiveness for her sinful adoption of an alien faith.
Sophronius Vrachanski also preached in the small church in the period when he was in town (1797 - 1803). The boyar church, as everyone calls it, had been neglected for 74 years until, in the summer of 1943, during the reign of Tsar Boris III, the Vratsa local Peter Buchinsky restored it. The temple was consecrated by Metropolitan Paisius, then head of the Vratsa Ecclesiastical Province. This is described in the stone inscription above the church. During communist rule, the church was again neglected and restored in 2017, with the image of St. Georgi featuring on its bell as homage to Georgi, the boyar who built it.
On September 13, 2018, new bell was consecrated by Metropolitan Gregory of Vratsa and priests of the diocese. The underground church is open to visitors.