The Bell Tower of St. Arnir (Croatian: Zvonik sv. Arnira) is all that remains of a Benedictine monastery built in 1069. It was later dedicated to St. Arnir, who was an archbishop of Split before being stoned to death in Poljica in 1180.
The complex was damaged in a fire in 1888 and was almost completely demolished in 1945, except for the bell tower and a small chapel. In the chapel, you can see the replica of St. Arnir’s sarcophagus (the original is located in Kaštel Lukšić.)
The bell tower is located outside of the north wall of Diocletian’s palace, right next to the statue of Gregory of Nin and the Golden Gate.