centuries By the 14th century the castle was losing its military importance. Alina de Mowbray ruled the Gower until 1331 when her son John de Mowbray took over as Lord of Gower. He was probably responsible for adding the arcaded parapet walk to the castle. Despite the Welsh rebellion led by Owain Glyndŵr, which saw a number of English castles attacked in the early years of the 1400s, it is not known whether Swansea fell to these forces. Swansea Castle's account books only record that two men were sent north to gather intelligence on Glyndŵr's activities. The castle owners were subsequently absentee landlords. By 1650 the castle was described as "a decayed Buildinge". By the 1670s the square tower was being used as a bottle factory and, in 1700, a town hall was built in the castle courtyard. By the mid 1700s the Great Hall had become Swansea's workhouse. The town hall was replaced by a post office in the 1800s and, by 1850, a military Drill Room had replaced the workhouse. The River Tawe, which had flowed near to the castle, was straightened and diverted during the 1840s. 20th and 21st centuries Part of the interior of the castle, in particular the large motte, was demolished 1909–1913 for the construction of a newspaper office. In the very early 1930s, poet Dylan Thomas worked for the South Wales Daily Post at the castle site. The newspaper offices were removed in 1976 and the remains of the castle were later consolidated and opened up to view from the street. As a Scheduled Ancient Monument, it was given a Grade I heritage listing in 1952. The castle was fenced off and only opened to the public on rare occasions, most recently for public tours in 2012 to coincide with St Davids Day. In the early 2010s a project was launched, funded by the European Regional Development Fund and Welsh Government, to open up the castle to the public on a more permanent basis with a stone paved courtyard and information panels. Demountable stairs were planned, to access the upper floors. The intention was to have public tours, events such as markets and for the castle to feature as part of a Swansea castle trail. Sources B Morris, Swansea Castle; RCAHMW, Glamorgan, Vol III, part (1b), The Later Castles (2000). RCAHMW An Inventory of the Ancient Monuments in Glamorgan: Volume III: Part 1a