The well was built in the period from 1717 to 1731, during the Austrian Baroque reconstruction of the fortress. On the plans of the fortress of the time this building is designated as “Big Well”. The name “Roman Well” was first recorded in the nineteenth century, and was based on folk tales that the old building, whose origins are forgotten, often attributed to the Romans. Through a hallway leads to the central area with a well diameter of 3:40 in depth about 51m (bottom of the well is lower than the bottom of the river Sava). A set of two spiral staircases, one of which served to launching a second climbing humans and livestock, descends into the well to a depth of 35.30m, which is semicircular hall.