City and port of southwestern England, a unitary authority and ceremonial county.
By late Anglo-Saxon England Bristol was becoming an important port in trade with Ireland, an importance that grew with the Anglo-Norman intervention in Ireland in the 1170s. In 1373 the suburb of Redcliffe across the River Avon, and so in Somerset, was included in the town, which was made a county of itself at the same time, so separating it from the jurisdiction of the sheriffs for Gloucestershire and Somerset. The creation of the diocese of Bristol in 1542 made Bristol a county of a city.
It became a county borough under the Local Government Act of 1888, when its borders were extended. By the Local Government Act of 1972 its ancient status as a county of a city and its administrative independence as a county borough were abolished, so that in 1974, when the Act became effective, it became a district in the new county of Avon.
In 1996, with the abolition of Avon, Bristol became an independent local authority again and also had its own Lord Lieutenant and High Sheriff. So the first of the ancient counties corporate became again what we might call a city and county of itself.
The diocese of 1542 consisted not only of Bristol and southernmost Gloucestershire (both in the diocese of Worcester until 1541) but also Dorset, previously in Salisbury, even though it lay beyond the Somerset diocese of Bath & Wells. In 1836, as part of the reforms that created two new Bishoprics in northern England, the dioceses of Gloucester and Bristol were combined, Dorset returning to Salisbury. In 1897 a separate Bishop of Bristol was again appointed, with responsibility for Swindon and north Wiltshire, but not Dorset.