Hay-On-Wye (in Welsh “Y Gelli Gandryll”) is well known as "the town of books". It is home to the Hay Literature Festival which brings some 80,000 writers, publishers and literature fans from all across the world to this small market town in south east Powys at end of May each year.

During the rest of the year this pretty market town is the United Kingdoms mecca for books, boasting thirty major bookshops, mostly selling second hand publications. It was world’s first Book Town. It all started in 1961 when Richard Booth opened his first bookshop in Hay, which soon grew into Europe's largest second hand bookshop.

Foremost amongst the town's landmarks is the impressive ruined castle. Dating from the 13th century, like so many border castles in Wales it was significantly damaged by Glyndwr's rebellion in 1400. However, Hay Castle continued to be in use as a residence until the early 20th century.

Like Builth Wells, Hay actually has two castles. It is likely that Hay was first fortified by William Fitz Osbern during his penetration of south east Wales during the summer of 1070. Over subsequent generations, the castles passed into the hands of many notorious Norman families including the Neufmarches, the Braoses and the Bohuns.

The remains of this fortress now lie beneath the current castle ruins and mansion. Without a doubt, this was the castle recorded as 'castello de haia' that surrendered to Miles Gloucester in 1121 along with Bernard Neudmarches's daughter. In 1165, the last of Miles Gloucester's male descendents was killed in a nearby battle.

Hay-On-Wye Castle was handed to the care of the notoriously ruthless William de Braose. Under the Braose rulership, the castle seems to have been developed, and it is likely that the gatehouse which now stands beside the keep dates back from this period. A popular historic novel, The Lady of Hay by Barbaraa Erskine, vividly describes life at the castle and within the de Braose Family during this period. The last Braose of Brecon was hanged by Llewellyn ap Iorwerth in 1230, and the lordship of Hay-On-Wye passed to the Bohun family.

Llewellyn and his forces continued to ravage the lands of the Bohuns, and during one such attack in 1231, the town of Hay-On-Wye was badly burned, though the castle survived. The castle continued to see service and changed hands three times – at one point it was surrendered into the hands of the famous Simon de Montfort. The conquest of Wales by Edward I finally brought more peaceful times to this border town, but just over a century later both the town and castle came under attack once more by Welsh forces, when in 1401 Owain Glyndwr and his legions swept through the region.

During the later medieval period, the castle passed into the hands of the earls of Stafford, who were to become the unlucky dukes of Buckinghams during the Ward of the Roses. In 1660s James Boyle of Hereford began the construction of a new mansion on the north side of the castle, and demolished most of the curtain wall to improve the views. The mansion continues to be used today – not surprisingly for Hay – as a second hand bookstore.

The other castle remains are located close to St Mary's Church in Hay. It is a small but well-preserved motte. It was probably constructed by William Revel, a knight in the household of Bernard de Neufmarche. It may later have become the seat for the commote of Melinog, but has no further recorded history.

Hay was put on the map on April 1 1977 when book enthusiast Richard George William Pitt Booth declared Hay-On-Wye to be an independent kingdom, and nominated himself its monarch. Since then, Hay has developed a healthy tourism industry based on literary interests. It is twinned with Timbuktoo.