Carmarthen Castle is one of Wales most important castles. It was built around 1106 by Henry 1st of England. It was built near the site of Carmarthen's Roman Fort, taking advantage of a defensive position overlooking and controlling the river Towi and river access to the Welsh Princes lands of Deheubarth.
The castle was originally a Motte and Bailey but was rebuilt in stone with the shell keep built around 1230. The castle's walls encompassed parts of Carmarthen allowing a thriving medieval town to develop.
The castle has an interesting and violent history with many battles fought nearby over control of the castle, with one of the most famous incidents in the early 1400s when the castle was repeatedly taken by Owain Glyndwr during his rebellion, but recaptured by Henry VI himself.
The castle played a role in the later Civil War between 1642-45 when it was captured and recaptured before its eventual slighting in 1660, when the castle saw its remaining walls used as part of the County Gaol in the late 1600s, 1700s and 1800s.