The Church of St. John the Evangelist is the only medieval sacral structure of tho Proto-Romanesque style with deambulatory (passage around the altar) in the sanctuary on our territory, which makes it a truly remarkable monument. It reached our time in entirely reduced remnants after its function was repealed in the end of the 19th century because of its fragile state.

Recent research and reconstruction work have revalorised its specific parts through recomposition and partial restoration of the apse with deambulatory. which contains seven pillars and a system of arches and vaults. Particularly valuable are the capitals on top of the pillars decorated with skilfully carved acanthus and palm leaves that are stylised on the lines of the second half of the 11th century.

The original church was built in the 5th century as a three-naval basilica with a semicircular apse whose opening towards the main nave is wider than its width and. therefore, it is classified as a specific typological group of that kind of buildings. It was ornamented with mosaics with decorative motives appropriate for this period. Their fragments are preserved in the apse, the sanctuary and the southern nave. It was this typological definition of the sanctuary that allowed the construction of the passage around the altar in the second half of the 11th century in congruency with the new liturgical provisions, especially within the Benedictine Order to whom this monastery belongs to. The walls of the previous church were demolished to the ground level and new ones were erected with supporting pillars on the outer mantle as supporters to the big semi-spherical apse. In the middle of the sanctuary there was an altar with a martyr's tomb at the foot in which an early-Christian stone reliquary was stored with characteristic marks of Christ as the beginning and the end. the letters alpha and omega. Also there is a sign that belongs to this period with the names of masters Mundo and Radavito (ARTIFEX MVNDO CVM RADAVITO OPERA FECIT), which is on the lintel of the door on the northern wall.

A Romanesque bell-tower with a custody chapel for tho reliquaries was erected in the 12th century on the southern side of tho church. It was built right next to the sanctuary probably for particular liturgical reasons. Just as the preserved sign says (OPUS ELIE ET MARCI). the bell-tower was renewed and partially restored in 1471 by masters llija and Marko.

The church was restored a number of times, changing owners and purposes in tho course of history. From 1273 Franciscan Conventuals replaced the Benedictine monks. By the end of the 18th century and until its repeal in 1828 this was the centre of the diocese. The most significant changes were carried out in the beginning of the second half of the 15th century by master Andrija Aleši. He erected big chapels in the floral Venetian Gothic style in the first two square space segments of the church for the Cemotta and Scaffa families.

The Vice-Roy of the Sava-valley built his mansion in the thirties of the 20th century in the place of the abandoned remnants of the church and the monastery, of which the only visible parts are the cloister walls and capitulary auditorium.