The monastic community in St Davids was founded by Saint David, Abbot of Menevia, who died in 589. In 1115, with the area under Norman control, King Henry I of England appointed Bishop Bernard as Bishop of St Davids. He began to improve life within the community, and commenced construction of a new cathedral. The new cathedral was quickly constructed and Bishop Bernard consecrated it in 1131.
Henry II of England's visit in 1171 saw the following of David increase and the need for a larger cathedral. The present cathedral was begun in 1181 and completed not long after. Problems beset the new building and the community in its infancy: the collapse of the new tower in 1220 and earthquake damage in 1247/48.
Under Bishop Gower (1328–1347) the cathedral was modified further, with the rood screen and the Bishops Palace intended as permanent reminders of his episcopacy. In 1365, Bishop Adam Houghton and John of Gaunt began to build St Mary's College and a chantry. He later added the cloister, which connects it to the cathedral.
The episcopacy of Edward Vaughan (1509–1522) saw the building of the Holy Trinity chapel. This period also saw great developments for the nave, whose roof and Irish oak ceiling were constructed between 1530 and 1540. Bishop Barlow, unlike his predecessor as bishop, wished to suppress the following of David, and stripped St David's shrine of its jewels and confiscated the relics of St David and St Justinian in order to counteract 'superstition' in 1538. In 1540, the body of Edmund Tudor, Earl of Richmond and father of Henry VII, was brought to be entombed in front of the high altar from the dissolved Greyfriars' Priory in Carmarthen.
The establishment of the Commonwealth of England under Oliver Cromwell greatly affected many cathedrals and churches, and was particularly felt in St Davids. The cathedral was all but destroyed by Cromwell’s forces and the lead was stripped from the Bishops Palace roof.
The Welsh architect John Nash was commissioned to restore the west front in 1793 to repair the damage done two hundred years previously. Within a century the Nash west front had become unstable and the whole building was restored by George Gilbert Scott between 1862 and 1870. The lady chapel was restored by public subscription in 1901 and the eastern chapels were restored through a legacy of the Countess of Maidstone, granddaughter of Bishop John Jenkinson, between 1901 and 1910.
The 1960s saw the restoration of St Mary’s College as the cathedral hall, for the use of the cathedral parish and for use as an area for art exhibitions and poetry readings. It was dedicated by Archbishop Edwin Morris in 1966 and the inaugural event was a poetry reading by the renowned poet R. S. Thomas, who served as a vicar in the Bangor diocese.
The Gatehouse contains an exhibition designed to introduce the pilgrim/visitor to the history and life of the Cathedral today including its daily worship.There is information about St David himself, about mediaeval pilgrimage to St Davids (two trips to St Davids was equal to one to Rome itself), and the importance of St Davids. In mediaeval times St Davids occupied a strategic position at the junction of major land and sea routes between England, Wales and Ireland and therefore the monarch took an interest in St Davids, William the Conqueror visiting in 1081.
The Broch of Gurness is an Iron Age broch village. Settlement here began sometime between 500 and 200 BC. At the centre of the settlement is a stone tower or broch, which once probably reached a height of around 10 metres. Its interior is divided into sections by upright slabs. The tower features two skins of drystone walls, with stone-floored galleries in between. These are accessed by steps. Stone ledges suggest that there was once an upper storey with a timber floor. The roof would have been thatched, surrounded by a wall walk linked by stairs to the ground floor. The broch features two hearths and a subterranean stone cistern with steps leading down into it. It is thought to have some religious significance, relating to an Iron Age cult of the underground.
The remains of the central tower are up to 3.6 metres high, and the stone walls are up to 4.1 metres thick.