Pembrokeshire records indicate that there was an Iron Age hill fort on the site of the castle, although there is no physical evidence to suggest this at the present location.

[1] The Flemish settled in the area in 1108 to protect the main Norman stronghold at Pembroke Castle from Welsh raiders from the north.

[1] The vast majority of sources indicate that the structure was originally a Norman stone keep and bailey fortress, founded by the Englishman Gilbert de Clare, Marcher Earl of Pembroke in 1120.

In 1173 the castle had its first royal visit by Henry II of England, who passed by the town on coming back from a trip to Ireland.

[4] That year, King John passed Haverford in order to sail to Ireland, so as to crush a rebellion by the Normans there.

[1] In 1284 King Edward I and Queen Eleanor of Castile visited the castle for the first time during a royal pilgrimage to St Davids.

These works proved important later, as in 1405 the castle was strong enough to fend off an attack during Owain Glyndŵr's War of Welsh independence.

Over the centuries the castle was visited by numerous nobles and monarchs such as King Richard II and Oliver Cromwell.

In 1644 Haverfordwest Castle is documented as being occupied by the Royalists, but they abandoned it on misinterpreting the noises of cows for a Parliamentary army.

[5] Oliver Cromwell sent letters to the castle, ordering it to be destroyed in July 1648 and threatened to imprison the townsfolk unless it was demolished.

[6] A cell door, leg irons, the original lock from the castle gate and numerous artifacts are on display.