The northern gate to the walled town dates from the 2C and owes its name to the dark patina that covers the sandstone blocks. The gateway was designed for military use: assailants who forced their way through the outer gates would find themselves in an inner courtyard in which they could be attacked from all sides. In the 11C the fortified gateway flanked by two towers was transformed into a church on two levels, dedicated to St. Simeon. All that remains today is the Romanesque apse and the vestiges of some Rococo sculptures.