Cardiff claims to have the largest concentration of castles of any city in the world. As well as Cardiff Castle and Castell Coch, there are the remains of two Motte and Bailey castles in Radyr and Rhiwbina (both known as the "Twmpath", a Welsh word for a small mound), which along with a castle at Whitchurch (known as Treoda and destroyed by housing in the 1960s) formed an arc of fortifications which divided the Norman lordship from the Welsh lordship of Senghenydd. Further up the Cefn Cibwr ridge on the boundary with Caerphilly there is also another ruined castle, known as Castell Morgraig. Archaeological evidence suggests this castle was never finished, and it is debated whether the fortification was of Norman or Welsh origin. The concentration of these castles is indicative of the moveable nature of the border between the Norman lordship of Glamorgan, centred at Cardiff, and its Welsh neighbours to the north.