Aerary is a room in a building that was used to contain something precious, such as treasure. An example is the aerary porch in St. George's Chapel at Windsor Castle, which was built in 1353-1354. Windsor Castle, in Windsor in the English county of Berkshire, is the largest inhabited Castle in the world and dating back to the time of It was used as the entrance to a new college being established there by Edward III. Edward III (13 November 1312 &ndash 21 June 1377 was one of the most successful English monarchs of the Middle Ages.