Keynsham, United Kingdom

At the same time as the grand Roman villa was being excavated at Durley Hill Cemetery, a second smaller villa was discovered during the construction of Fry's Somerdale Chocolate Factory. Two fine stone coffins were found, interred with the remains of a man and a woman. The villa and coffins were removed to a place near the gates of the factory grounds, and construction on the factory went ahead. Fry's built in the grounds of the factory a museum which for many years housed the Durley Hill mosaics, the coffins, and numerous other artefacts. In 2012, Taylor Wimpey, about to develop the factory site, made a detailed geophysical assessment of the area, and discovered an additional 15 Roman buildings centred around a Roman road beneath Keynsham Hams, with evidence of additional Roman buildings that had been disturbed by quarrying.

According to legend, Saint Keyne, daughter of King Brychan of Brycheiniog (Brecon), lived here on the banks of the River Avon during the 5th century. Before settling here, she had been warned by the local King that the marshy area was swarming with snakes, which prevented habitation. St Keyne prayed to the heavens and turned the snakes to stone. The fossil ammonites found in the area were believed to be the result. However, there is no evidence that her cult was ever celebrated in Keynsham.

Some scattered archeological evidence suggests that an Anglo-Saxon settlement existed in Keynsham in the High Street area, and that in the 9th century a Minster church existed in Keynsham as well. The earliest documentary reference to Keynsham is in the Anglo-Saxon Chronicle, (c. 980) which refers to it as Cægineshamme, Old English for 'Cæga's Hamm.' The town is also listed in the Domesday Book of 1086 as "Cainesham." It has therefore been suggested that the origin of Keynsham's name is not, in fact Saint Keyne, but from "Ceagin (Caega)."

Around 1170, Keynsham Abbey was founded by the Victorine congregation of canon regulars. Archeological evidence suggests that the abbey was built over the site of the previous Saxon Minster church. The settlement developed into a medieval market town, and the abbey of Keynsham was given ownership of the Keynsham Hundred.

The abbey survived until the dissolution of the monasteries in 1539, and a house was subsequently built on the site. The remains have been designated as a Grade I listed building by English Heritage.

Keynsham played a part in the Civil War as the Roundheads occupied the town and also camped there for the night, using the pub now known as the Lock Keeper Inn as a guard post. During the Monmouth Rebellion of 1685 the town was the site of a battle between royalist forces and the rebel Duke of Monmouth. Bridges Almshouses were built around 1685 and may have been for the widows of those killed in the rebellion.

Keynsham rose to fame during the late 1950s and early 1960s when it featured in a long-running series of advertisements on Radio Luxembourg for Horace Batchelor's Infra-draw betting system. To obtain the system, listeners had to write to Batchelor's Keynsham post office box, and Keynsham was always painstakingly spelled out on-air, with Batchelor famously intoning "Keynsham – spelt K-E-Y-N-S-H-A-M – Keynsham, Bristol". This was done because the proper pronunciation of Keynsham – "Cane-sham" – does not make the spelling of Keynsham immediately obvious to the radio listener.

Since the 1950s Keynsham has become a dormitory town for Bristol and Bath. The High Street shopping area has been remodelled, and a Town Hall, Library, and Clock Tower were built in the mid-1960s.

Before the creation of Chew Valley Lake and river level controls at Keynsham Lock and weir, Keynsham was prone to flooding. The Great Flood of 1968 inundated large parts of the town, destroying the town's bridges including the county bridge over the Avon which had stood since medieval times, and private premises on Dapps Hill; the devastation was viewed by the Duke of Edinburgh. After the flood the Memorial Park, which had been laid out after World War II was extended.

Design work for regeneration of the town hall area was awarded by Bath and North East Somerset Council to Aedas in 2010, with the works cost stated in 2011 to be £33 million (£34 million in 2012). Realisation of the plans is hoped to "attract new business and jobs", in the aftermath of the announcement of the Cadbury Somerdale Factory closure.

In January 2012, it was announced that the Willmott Dixon Group had been appointed as contractor on the scheme. The council's planning committee in August 2012 deferred the approval decision, pending alterations to the external appearance of the building. These were approved in October 2012, with demolition commencing in the same month. The regenerated Keynsham Civic Centre came back into use in late 2014 and early 2015.

In the latter half of the 2010s, Keynsham underwent rapid expansion with hundreds of new homes built.