The town of Varaždin was surrounded by a fortification in the shape of an irregular quadrilateral with bastions, semi-circular half towers and north and south town gates which were entered across wooden bridges stretching over a moat. According to historical sources, its construction was associated with the impending threat to the wider area of the Kingdom of Croatia and Styria in the second half of the 15th century, while the underlying mediaeval fortification layer that preceded it has not been sufficiently researched yet. Although the exact time of the beginning of its construction remains unknown, the existence and construction of the walls is mentioned in the sources as early as 1516. Some elements indicating the appearance of the fortification around the settlement before it was modernised are known from historical sources, but its final transformation occurred in the Renaissance during the restoration of the feudal fortification into a Wasserburg, when these two elements were connected with a shared fortification system. Apart from repairs, after this period there were no significant interventions on the fortification until the second half of the 18th century, when the east and west walls were breached for the purpose of urban development and to facilitate transport. At the beginning of the 19th century the fortification was systematically demolished, leaving only the foundations of the walls beneath the street level and individual segments in the foundations of houses.