Downpatrick, United Kingdom

In the early 11th century, a much bigger fort with earthen ramparts was built on the northern drumlin, now known as the 'Mound of Down'. This was the capital of the Dál Fiatach, the main ruling dynasty of Ulaidh (Ulster), who held the title "Rí Uladh", "King of Ulster". Deirdre Flanagan suggests that the older name Dún Lethglaise referred to Cathedral Hill, while Dún da Lethglas was the name of this new royal residence.

The King of Norway, Magnus Barefoot, was killed in an ambush near Downpatrick in 1102. It is believed his grave is marked by a mound at Horse Island, southwest of Cathedral Hill.

Saint Malachy became the Bishop of Down (Dún da Lethglas) in 1137. He administered the diocese from Bangor and introduced a community of Augustinians (canons) to Dún da Lethglas dedicated to St John the Evangelist. Malachy and his successors repaired and enlarged Down Cathedral.

In the late 12th century, the area was conquered by Anglo-Normans led by John de Courcy, becoming part of his Earldom of Ulster. In February 1177, a Norman army of 300 men and 20 knights marched north from Dublin and took the town by surprise. The King of Ulster and Dál Fiatach, Ruaidrí mac Duinn Sléibe (Rory MacDunleavy), tried to retake the town, but was forced to withdraw after a fierce battle. The Normans began building a motte (fortified mound) inside the older royal fort, but abandoned it when de Courcy made Carrickfergus his capital in 1178.

In 1183, de Courcy brought in Benedictine monks from the abbey of St Werburgh in Chester (today Chester Cathedral), England. He built a friary for them at Downpatrick; this building was destroyed by an earthquake in 1245. He also re-dedicated the cathedral to Saint Patrick, giving it the name Ecclesia S. Patricii Duni in Latin. It is claimed that de Courcy miraculously found the bones of St Patrick, St Brigid and St Colmcille at Downpatrick. In the presence of the Papal Legate, Vivian, the relics were reburied inside the cathedral on 9 June 1196. This story of their discovery is thought to have been crafted by de Courcy for political reasons. In the Anglo-Norman and later medieval era the town's name in Latin and English documentation is variously 'Dunum', 'Dun' or 'Down'. The oldest surviving record of the name 'Downpatrick' is in the Bodley Survey of the early 1600s.

In 1260 Brian O'Neill, King of Tír Eoghain (Tyrone) and claimed High King of Ireland, marched to Downpatrick, which was then part of the Anglo-Norman earldom of Ulster. Allied with a Connacht force under Hugh O'Conor, he fought the Anglo-Normans in the Battle of Down. O'Neill was killed and the Irish were defeated. The death of O'Neill and defeat of the Irish was lamented in a poem by the Cenél nEógain bard Giolla Brighde Mac Con Midhe (1210–1272).

The earldom collapsed in the 1300s, but the English retained a foothold in Lecale. In 1375, Niall O'Neill of Tyrone defeated the English at Dundalethglas.

Under orders from King Henry VIII of England, Downpatrick's monastic community was dissolved by the English around 1540, and the cathedral fell into ruins. In 1600, the cathedral was allegedly burnt by English forces led by Edward Cromwell. A painting from 1788 shows the abbey ruins and its round tower.

The Archbishop of Armagh, composer of Irish bardic poetry and Christian poetry in the Classical Gaelic literary language, and Franciscan Counter-Reformation theologian Aodh Mac Cathmhaoil was born outside Downpatrick in 1571. On 21 January 1575, Franciscans John Lochran, Donagh O'Rorke, and Edmund Fitzsimon were hanged by Protestants at Downpatrick.

After his 25 April 1681 assassination by his foster brother, Art McCall O'Hanlon near Hilltown, County Down, rapparee leader Count Redmond O'Hanlon's severed head was displayed spiked upon Downpatrick Gaol. The count's body was buried in the Roman Catholic cemetery at Ballynabeck, on the road between Tandragee and Scarva.

Cathedral Hill was the subject of an archaeological investigation in series 5 of the Channel 4 Time Team programme.

Four main thoroughfares are shown converging on a town plan of 1724, namely English Street, Scotch (now Saul) Street, Barrack (now Scotch) Street, and Irish Street. The landscape limited the growth of the town. The early-18th-century street plan continued largely unchanged until 1838 when Church Street was built, followed by Market Street in 1846.