The Balbi Arch is the main entrance to the old town of Rovinj. Here was one of the 7 main gates to the city, which dates back to ancient times. This was demolished in 1678/79 and replaced by the current gate. The builder was the mayor at the time, Daniel Balbi, hence the name.
The place where this arch is today used to be the main gate of the fortified town, Porton della pescheria. In the period between 1678 and 1679, the old town gate was torn down and the Balbi Arch was built in its place. It was built during the time when Daniel Balbi was mayor of the town, as the inscription on the stone tablet attached to the arch attests. Source: rovinj tourism