Castle Quarter (Welsh: Cwr y Castell) is a commercial area in the north of the city centre of Cardiff, Wales.The Castle Quarter includes some of Cardiff's Victorian and Edwardian arcades: Castle Arcade, High Street Arcade and Duke Street Arcade, and principal shopping streets: St Mary Street, High Street, Castle Street and Duke Street.Development of the area began in February 2010 and is expected to be completed by July 2011.