© 2001-2016 by Marvin Hull
Originally the word solar, or soller, was used to describe any room above the ground level of a building. It refers to a well lighted parlour or chamber facing south, no matter the floor level.

In relation to the castle, the solar or great chamber was the lord's private apartment, or withdrawing room. Its location was beyond the dais (a raised platform for the high table) or high table end of the hall, usually on the first floor level over an undercroft (plain room used for storage). Sometimes, builders placed a solar in a mural tower or in the keep. In a keep, the solar was located on the protected side so that it could have windows instead of slits to take advantage of the sun. In later medieval fortified manor houses, the solar wing was located in a tower.

Oftentimes the lady of the castle reserved the solar for her use. This type of solar or apartment is referred to as a bower. These often had elaborately plastered walls and decorative fireplaces. The bower became an essential part of medieval domestic accommodation.

It is unclear what date solars first came into use, or who was responsible for their invention.