In 1107, William Warelwast, a nephew of William the Conqueror, was appointed to the see, and this was the catalyst for the building of a new cathedral in the Norman style. Its official foundation was in 1133, after Warelwast's time, but it took many more years to complete. In 1258 the building was already outmoded, and it was rebuilt in the Decorated English Gothic architecture style, following the example of nearby Salisbury Cathedral. However, much of the Norman building was kept, including the two massive square towers and part of the walls. It was constructed entirely of local stone, including Purbeck Marble. The new cathedral was complete by about 1400, apart from the addition of the chapter house and chantry chapels.