It originated in a monastery founded by St Columb, about 545, of which some of the abbots at a very early period were styled bishops; but the title of Bishop of Derry was not established until 1158, or even a century later, as the bishops, whose see was at Derry, were sometimes called Bishops of Tyrone.
The see first existed at Ardstraw, where St Eugene, the first bishop, died about the end of the 6th century.
It was subsequently removed to Maghera, whence it was transferred to Londonderry.
By an inquisition in 1622, the bishop was found to be entitled to fish for salmon on the Monday after the 4th June, within the great net fishery belonging to the London Society; also to half the tithe of salmon, etc, caught in the River Bann and Lough Foyle.
Bishop Hopkins, who died in 1690, was at great expense in beautifying the cathedral, and furnishing it with organs and massive plate; and is said to have spent £1,000 in buildings and other improvements in this diocese and that of Raphoe.
Derry continued to be a separate bishopric until the death of Dr Bissett, Lord Bishop of Raphoe, in 1836, when that see was annexed to the diocese of Derry, and its temporalities became vested in the Ecclesiastical Commissioners.
Its greatest length is 60 miles, and its greatest breadth 54 miles, extending into four counties.
It comprises parts of counties Londonderry, Tyrone, Donegal, and Antrim.
THE PALACE, Londonderry, County Londonderry, adjoining the cathedral, was built in 1753 by the Right Rev William Barnard, Lord Bishop of Derry, 1747-68.
It comprises a square Georgian block of three storeys over a high basement.
It is thought that the palace was extended ca 1800 by the Earl-Bishop, Frederick Hervey.
It was damaged in 1802 while occupied as a barrack and subsequently repaired by the Right Rev and Hon William Knox.
The palace was sold by the Church of Ireland in 1946 to the Freemasons.