The Kahal Kadosh Yashan Synagogue on Justinianos Street is located inside the walled Castro, near the Big Gate. The family clans who worshiped there include the Levy, Negrin and Coffina.
Because of the location of the synagogue, they were called insiders (mesinoi). The original structure likely dates to the Byzantine period. It is not clear whether it was constructed on the site of an earlier synagogue or if it is the first official house of worship of the Ioannina Jews. A tall, stone wall encloses the synagogue and its property. Although the synagogue has been restored twice, in 1881 and in 1987, the building still retains its original character.