the Palas and the Landvogt's residence and protect the castle from cannon bombardment from the Goffersberg. The adjacent residence was covered by a huge earthen embankment which absorbed moisture and rendered the building uninhabitable. In 1659, a clocktower was built on the east bastion; its pointed roof was replaced in 1760 with an onion dome. In 1893–94, the exterior wall was lowered by 6.5 m, making it possible to free the walled-up windows on the south side of the Landvogt's residence, and to dry out the walls. A rose garden was laid out on top of the now lower embankment. During the comprehensive renovation of 1978–86, the last remnant of the embankment was removed and a basement level excavated, which now houses part of the Aargau Museum. Palas The Palas (residence of the Count) was built in 1100 as a 4-storey, 18 m high fortified building. Together with the adjacent tower, it is one of the oldest buildings in the castle complex. The entrance was originally on the second floor, accessible only by way of a wooden outdoor staircase. The main floor had a fireplace, the top floor had the sleeping accommodations, and the lower two floors were storerooms. During the period of the Bernese Landvögte, the building was called the "Kill" because the torture chamber was located in it. In 1598–99 a new arched entrance was built on the ground floor. Between 1978 and 1986, the division of the floors and connection to the stairs were rearranged to make it possible to use the building for the Historical Museum. Tower The tower (also called the South Keep) is 10 m square and has walls 3 m thick. It was built on to the Palas around 1170 and used its west end as a boundary wall. After the death of Ulrich IV, who had ordered it built, the work stopped and the building remained incomplete for almost 200 years. It was only finished in 1344. During the period of Bernese rule, beginning approximately in the early 17th century, the gaol was located on the first floor; it can still be visited today. To create more storage space for grain, in 1728–29 the tower and the neighbouring Knights' Hall, and the well between them, were joined with an unornamented utility building. This required the removal of the north façade, because the tower was not aligned with the Knights' Hall. In 1896,