Conwy Castle and the town walls were built, on the instruction of Edward I of England, between 1283 and 1289, as part of his conquest of the principality of Wales. The church standing in Conwy has been marked as the oldest building in Conwy and has stood in the walls of Conwy since the 14th century. However, the oldest structure is part of the town walls, at the southern end of the east side. Here one wall and the tower of a Llys [palace/court house] belonging to Llywelyn the Great and his grandson Llywelyn ap Gruffydd have been incorporated into the wall. Built on a rocky outcrop, with an apsidal tower, it is a classic, native, Welsh build and stands out from the rest of the town walls, due to the presence of four window openings. It dates from the early 13th century and is the most complete remnant of any of his Llys.