The medieval city of Limerick is largely concentrated on the southern section of Kings Island known as Englishtown and south of the Abbey river in an area known as Irishtown, just to the north of the present day city center. The island contains some of Limerick's main attractions including King John's Castle which was completed in around 1200. The walls, towers and fortifications remain today. The remains of a Viking settlement was also uncovered during the construction of the visitor centre at the site. St. Mary's Cathedral was founded in 1168 and is recorded as the oldest building in Limerick. It was built on an earlier castle belonging to the King of Munster. Nicholas street and Mary Street the medieval center of Limerick contained many examples of medieval buildings including tall gabled houses in the Flemish or Dutch fashion. Unfortunately, very little, if any of this streetscape remains today. Following the development of Newtown Pery this area of the city went into decline. Today both the Englishtown and Irishtown areas remain neglected and dilapidated in appearance.