Canterbury is a historic English cathedral city and UNESCO World Heritage Site, which lies at the heart of the City of Canterbury, a local government district of Kent in the United Kingdom. The Archbishop of Canterbury is the primate of the Church of England and the worldwide Anglican Communion owing to the importance of St Augustine, who served as the apostle to the pagan Kingdom of Kent around the turn of the 7th century. Many historical structures fill the area, including a city wall founded in Roman times and rebuilt in the 14th century, the ruins of St Augustine's Abbey and a Norman castle, and perhaps the oldest school in England, The King's School.