A dramatic view of the ruined castle from the landward side. We can see the very beautiful Cardigan Bay on the left. The Castle and its landscaped grounds are now Grade I listed. The New Promenade and National Cycle track, which goes along the seafront below the ruins, go round part of the perimeter today.

In 1878 the town of Aberystwyth was described as "a delightful watering place and fashionable resort" on the edge of the bay. "Amongst the first objects of interest to the visitor are the ruins of the once formidable castle, which occupies the summit of an elevated promontory. It was built by Gilbert de Strongbow in the reign of Henry I. After being the scene of many conflicts it was destroyed by Owen Gwynedd. Edward I. rebuilt a castle on the old site, the ruins of which remain^[1]."

Two years later a trades directory mentioned the houses of Marine Terrace, which are also close by. They were said to be "a beautiful level space at the margin of the sea", and "very charming residences". "The castle grounds, close to the beach, offer a most attractive lounge to visitors, and perhaps there is no station southward of Caernarvonshire from which the Welsh Alps may be more advantageously seen than from the castle grounds. The castle was supposed to have been built by Gilbert Strongbow in 1190, destroyed by one Machgwyn, and afterwards rebuilt by Llewellyn ap Iorwerth, Prince of North Wales, but the present ruins are the remains of a castle erected by Edward in 1277, which was blown up by order of Parliament in 1646 ^[2]".

A local barrister recounted more of the castle's history in 1879. "Two hundred years ago the ruins of Aberystwith Castle were described as "confused heaps of unnecessary rubbidge" by John Taylor, The Water Poet, riding into the town in the summer of 1652". Edward I, in the 6th year of his reign, granted a charter to the town and created it as a free borough. Aberystwith was frequently called Llanbadarn at the time. Edward, the Black Prince, sent his commissioners into Wales.He visited in 11 August 1343, when John de Montgomery was the castle's constable. Owen Glydwr took possession in 1403 and retained it for some time^[3].

At the start of the Civil War the castle was garrisoned for the King, Charles I. Thomas Bushell was a stout partisan of the King; he had also been granted the Mines Royal. He established a mint at the Castle to aid the King and made silver coins here in 1642 and 1643. The Castle was besieged in November 1645, and was successfully held by Col. Richard Whiteley. On the Parliamentary side was Col. Rice Powell, aided by Col. Jones of Nanteos. They held out until the following April (12 April 1646?) before surrendering. Phillips added that Cromwell himself was never at Aberystwith; the castle was demolished following an order of Parliament shortly after the King's execution, as were many others. It was to ensure that castles could no longer be used for the disturbance of the country^[3].

Bushell was said to have clothed the King's entire Army. However, when the Castle fell to the Parliamentary forces the mines were abandoned although post Restoration (of Charles II) they were returned to the company of mines adventurers; the Earl of Pembroke was the governor^[4].

I have used the then contemporary spelling for Aberystwyth when quoting from old books and newspaper articles to provide some background information.

There are two excellent sites, both with accompanying historical notes, with photographs of the ruined castle today:
Aberystwyth Castle, part of the Aberystwyth web site.

Aberystwyth Castle, part of the Castles of Wales web site.

References:

^[1] "Wales Register & Guide, 1878", (First Issue). Aberystwith.

^[2] "Slater's Directory of North and South Wales etc.", (1880), [Part 1: N & S Wales]. Aberystwith.

^[3] "Cardiff Times", 29 March 1879. The Castles and Abbeys of South Wales and Monmouth by J. Roland Phillips, Barrister at Law, XVIII. Aberystwith Castle.

^[4] "Daily News", 10 February 1862.