Gloucester was from its foundation in the 1st century AD as a Roman fort defended by a perimeter with north, east, south and west gates. The sites of these original four gates of Gloucester today are:
* Northgate Street between Hare Lane and St. Aldate Street, marked by large cobbling across the road;
* Eastgate Street at the beginning of the pedestrianised zone, where the subterranean remains of the medieval gate can be seen today in the Eastgate Viewing Chamber;
* Southgate Street, at the beginning of the pedestrianised zone, where a modern sculpture in metal has been installed along the line of the old wall west of the gate and a section of the old wall can still be seen in the furniture store on the corner opposite;
* Westgate Street, on the site now occupied by the building on the corner with Berkeley Street (the modern Westgate Street runs slightly north of its original Roman alignment, while Berkeley Street straddles the line of Roman Wall according to some sources, or runs just outside the wall according to others).
Gloucester was left to ruin after the Romans abandoned Britain in the early-5th century. It's possible the Saxons, who moved into the area in the 6th century but did not start repopulating the former Roman colony until the 9th or 10th centuries, maintained the old Roman walls. Archaeological evidence indicates, however, that as they established Saxon Gloucester they began building outside those walls to the west and north.
It's not known exactly when the western Roman wall was dismantled, but it no longer existed by the time of the early Norman period. It's possible that it was dismantled by the laying down of Berkeley Street and the extension of the Saxon town to the line of the Old Severn (a now extinct channel of the Severn that ran along the line of today's Lower Quay Street approximately 260 yards (240 metres) outside the Roman west gate). A Roman riverside wall and quay there was not dismantled until the 12th century. The Norman abbey begun in 1089 and known today as Gloucester Cathedral cut across the north-west corner of the wall, and the first of city's two Norman castles was extended across the wall at its southern end.
To the north, Saxon suburbs extended beyond the walls – Hare Lane, St. Catherine Street (which in its original incarnation was known as Watering Street and ran from St. Oswald's Priory), Lower Northgate Street (between the Roman north gate and today's Northgate Street junction with Black Dog and Bruton Ways), and Alvin Street (originally known as Fete Lane) are all Saxon in origin.
There is archaeological evidence that Gloucester's defences were rebuilt partly on the Roman defensive system shortly after the Norman Conquest of 1066. This re-established the walls around the eastern half of Gloucester, from the north gate round to the south gate. Within a few years of the consecration of the abbey c.1100, the abbey precinct was walled, and when the abbey expanded onto land belonging to St. Oswald's Priory c.1218 the wall was extended.
The precinct wall (a stretch of which still stands along Pitt Street from the entrance to King's School to the junction with St. Mary Street) became, along with the St. Oswald's Priory precinct, part of Gloucester's northern defences, extending west from the Roman perimeter to the Old Severn. Continued conflict between town and abbey about who was responsible for the wall was settled in 1447. The agreement required the abbey to guarantee that no breaches would be made in the north wall. Today's entrance into the precinct from Pitt Street, known as the infirmary gate, was not established until as late as 1673, a decade or so after the city's walls were pulled down.
Gloucester's defences were extended from the south-west corner of the Roman perimeter to the Severn in the early 12th century by the construction of Gloucester Castle, above today's entrance to the Docks (the castle, once fit for a king, was in later centuries neglected to the point of ruin and demolished in 1787 to make way for Gloucester Prison, itself now being dismantled).
Documentary evidence of Gloucester's medieval gates appears for the first time in the 12th century; north and south gates are mentioned in the 1140s. In 1181 Alvin Gate, located on bank of the River Twyver at the top of Hare Line, appears for the first time in the records. Another new gate, the outer north gate, was also established on the bank of the Twyver, at the junction of today's Northgate Street with Black Dog and Bruton Ways. The Twyver at this time marked the north-eastern boundary of the city, though there is no evidence of any defences other than the river between the two new medieval gates.
Following the construction in 1119 of Foreign Bridge over the Old Severn (outside today's Westgate Street car park and where Royal Oak Road now bisects Westgate Street), Gloucester annexed the land across the bridge (later known as the Island, where today's Westgate Retail Park is located). A new west gate, referred to in the early 13th century as a castle, was established on what, after a change in the course of the Severn, soon became the bank of the Severn's east channel.
Several gates appear in the records of the mid-13th century. The old east gate (also known as Ailes Gate) was rebuilt with a substantial bastion. A new postern gate was installed in the north-east corner of the wall, marked today by the gap in the corner of King's Square leading to the bus station. It's likely that at the same time a second postern gate, mentioned in 1509, was installed in the south-east corner, in the area where today Brunswick Road meets Parliament Street.
By the late-15th century Alvin Gate, outer north gate, east gate, south gate, and the new west gate on the Severn were all official, toll-collecting gateways into the city manned by porters. The gates included rooms, and two gates served as prisons. The main prison was in the inner north gate and the other probably the east gate (known to incarcerate female prisoners in 1560 and used from 1613 as a 'house of correction'). Trade companies are known to have used gate rooms as meeting venues in the 16th century.
Alvin Gate was apparently destroyed in 1643, during the English Civil War siege of Gloucester. The south gate was also damaged to the point of collapse during the siege and rebuilt the next year. The city's walls were pulled down after the restoration of the monarchy in 1660. The perimeter gate structures survived, albeit with gates themselves removed. They increasingly became obstacles to traffic in the 18th century and were eventually dismantled. Blind Gate is known to have still existed in 1724, but was recorded in 1783 as having been dismantled "many years previously." The east gate was dismantled in 1778, and the north, outer north and south gates followed it into history three years later (the doors of the south gate are now held by the Folk of Gloucester). The last gate to go was the substantial, fortified gate house on Westgate Bridge, demolished 1806 in preparation for the replacement ten years later of the bridge.
A History of the County of Gloucester: Volume 4, the City of Gloucester, Victoria County History, 1988:
The Severn Flood-Plain at Gloucester in the Medieval and Early Modern Periods, Transactions of the Bristol and Gloucestershire Archaeological Society, 2006, John Rhodes