The construction of the Franciscan Monastery of St. Nicholas, which was inhabited only by "Conventuals" was started in 1288 and it was initiated by Queen Helen of Anjou, wife of the Serbian King Uros I. She also equipped the monastery with all the necessary church objects.
Archeological research done in 1951 and 1952 under the direction of Professor Durde Boskovic showed it was a singel-nave building with a rectangular apse facing east. there was a small rectangular chapel along the eastern part of the north side which the apse remained. There was a bell-tower on the west side. The cella was vaulted with the vaulting lightly fractured at the column. Today it is possible to detect the way the walls were built by examining the ruins lying all around the church.
There weas a thin long gothic window on the western facade and above it there was an oculus (a decorative hole). The inside was tiled with polished tiles of various dimensions. Under the floor there were the storey-tombs of the nobility of Bar which had consoles, or wall-brackets, for constructing tombstones on many levels.
Pope Pius II initiated the church restauration which was definitely completed by the second part of the 15th century. In 1458 he granted an indulgence to everyone who helped this process.
The church was turned into the Orta Mosque after the 16th century and it was destroyed in an ammunition explosion in 1912.
Within the Franciscan Monastery complex of St Nicholas there was also a small chapel with two rooms without a space for the altar or the apse. Its facade was constructed in the "Romanesque" fashion (fine-dressed stone blocks of unequal sizes put in regular lines). Behinde this chapel which was dedicated to St Mark according to tradition, there also used to be the monastery's monastery cloister which was completely ruined when the Ottomans  built a gunpowder-magazine instead.