thumb|right|180px|Down Cathedral, August 2009
thumb|The reputed burial place of [[Saint Patrick.]]
Down Cathedral, the Cathedral Church of the Holy and Undivided Trinity, is a Church of Ireland cathedral located in the town of Downpatrick in Northern Ireland. It stands on Cathedral Hill overlooking the town. It is one of two cathedrals in the Diocese of Down and Dromore (the other is Dromore Cathedral). The cathedral is the centre point of Downpatrick, a relatively new name for the settlement, having only come into usage in the seventeenth century.
Although not as ancient or carrying such well-attested historical importance as nearby Bangor Abbey, there is little doubt that in the period of the Celtic church, when monasticism was such a hallmark of Christian settlements, that a community of monks lived on - or near - the hill overlooking the Quoile.
The royal charter was granted to Down Cathedral on 20 July 1609.
John Wesley visited Downpatrick four times between 1778 and 1789 and on each occasion preached in the Grove on the hill of Down Cathedral. A memorial stone marking his mission can be seen there today.
Restoration
The cathedral incorporates parts of the 13th-century church of the Benedictine Abbey of Down (Black Monks). It lay in ruins after the dissolution of the monastery in 1541. It reopened for divine service on 23 August 1818.
Two small stone crosses now built into a wall in Down Cathedral appear to be 12th-century work and are carved with monks holding books.