The church was built in the second half of the 12th century and is in Romanesque style. Each of the three naves ends with an apse. Extensions that took place shortly afterwards lasted until 1392, which also led to a change in style: the west façade is clearly Gothic. Following an earthquake in 1460, the façade was redesigned by 1488. Renaissance elements can be found especially on the portal.
Interior.
At the beginning of the 18th century, Koper was under Venetian influence, which led to a redesign in the Baroque style. Giorgio Massari was responsible for the redesign. Additional furnishings were brought into the church, including valuable paintings by Venetian painters Pietro Liberi, Andrea Celesti, Beltrame, Antonio Zanchi and Gianelli, as well as by Bendetto and Vittore Carpaccio. The most important painting, the “Sacra Conversazione” by Vittore Carpaccio, dates from 1516. The sarcophagus of Saint Nazarius dates from the 14th century and was probably created by Filippo de Sanctis.