Aberystwyth Castle, located on the west coast of Wales, is one of the few large castles in Ceredigion proper. To the east is mountainous terrain and it guards the entire north/south coast of Wales. A fort has existed in the area since prehistoric times, and over the centuries, different peoples have added to, knocked down, and rebuilt multiple fortifications.
The first ‘castle’ at Aberystwyth was on Pen Dinas. It is an iron age hill fort, overlooking both the sea and the city of Aberystwyth. It was occupied for about 300 years, into the first century BC.
“The ridged top site is enclosed by a series of banks and ditches.There have been numerous finds on the site and most are now in the hands of the National Museum of Wales. They include a clay pot made in the Malvern Hills and a pale yellow glass bead, possibly made in Somerset, as well as decorated Iron Age pottery, a 4th century Roman coin, spindle whorls and loom weights.” http://www.bbc.co.uk/wales/mid/sites/celts/pages/pendinas.shtml
Although other fortifications followed, the first true castle wasn’t built until the 12th century, with the coming of the Normans. Traces of that castle, an earthen and wood construction, Tan-y-castell, are still visible alongside the River Ystwyth. It was burned by Gruffydd ap Rhys, Prince of Deheubarth, in 1135, and then rebuilt by Cadwaladr ap Gruffydd, Owain Gwynedd’s wayward brother, when he took over Ceredigion. http://www.castles.me.uk/aberystwyth-castle.htm
Llywelyn ap Iowerth (Llywelyn the Great) began the first stone castle in a different location by the sea, rather than on the heights. http://www.castlewales.com/aberystw.html
This castle was then rebuilt beginning in 1277 by Edward I in his castle building program (See my blog, An Iron Ring of Castles). Dafydd ap Gruffydd’s Palm Sunday insurrection in 1282 burned it, but at the Welsh defeat, Edward continued the building and it was completed in 1289.
“In 1404, the castle fell to Owain Glyndwr and it was occupied until being recaptured by cannon in 1408. During this occupation it became an important seat of Welsh government. In 1637 the castle was chosen by Charles I to house a royal mint. Coins of eight different denominations were produced from local silver. All carried the emblem of the Prince of Wales feathers.
Charles Bushell, who operated the mint in 1637, became very wealthy. At the start of the Civil War he lent Charles I £40,000 and raised a regiment of soldiers made up from local miners. Bushell’s mint was closed down during the Civil War, but was used to store silver and lead. Garrisoned by Royalists, the castle was besieged by the Parliamentarians and surrendered in 1646. Cromwell’s troops made a good job of demolishing the building, thus preventing it ever being used again.” http://www.bbc.co.uk/wales/history/sites/themes/society/castles_aberystwyth.shtml