The slate pillar fence at Bisham (Windsor and Maidenhead). Approximately 150m (164 yards) of this fence survives, although local residents remember it as once being significantly longer. The pillars of Bisham's fence typically extend about 180cm (5.9 feet) above ground level and must have a further 40cm (1.3 feet) or so below the ground. Each pillar is some 20cm (7.9 inches) in width and 3.5cm (1.4 inches) thick.

How did a slate pillar fence come to be built in the Thames Valley, 300km away from the slate quarries of north-west Wales?

Slate pillar fences became common in north-west Wales from the middle of the 19th century. In 1861, the Penryhn Quarry at Bethesda, Gwynedd - one of the largest slate quarries in the world at that time - produced around 9,000 individual pillars. These pillars consisted of poor quality blue slate, typically about 150cm (4.9 feet) tall.

They were used to mark fields, gardens, railways lines and roads, with their simple construction being particularly well-suited to the harsh weather experienced by upland areas.

Despite their use around Wales's slate quarries, slate pillar fences are rarely found further a field. The discovery of a slate pillar fence at Temple House (now demolished) at Bisham, Maidenhead, is therefore extremely unusual. The bluish-purple colouring of the slate makes it certain that it was quarried in north-west Wales, probably at Penrhyn Quarry.

This raises the question of how a slate pillar fence came to be built almost 300km (186 miles) away from the source of the stone?

Temple House was built around 1790 for Thomas Williams, who owned the nearby Temple Mill copper works. Thomas Williams (1737-1802) was from north Wales originally and became the leading figure of the British copper industry. Williams employed the architect, Samuel Wyatt, to develop the Temple Mill copper works, and it is likely that Samuel also built Temple House.

Samuel Wyatt had very close links with the owners of the Penrhyn slate quarry. In 1782 he refurbished a building for Richard Pennant (later Lord Penrhyn), and in 1786 his brother became the general manager of the Penrhyn estate. This relationship ensured Samuel a regular supply of slates for his own business activities. In return, Samuel promoted the use of slate in the London area, using it for shelves, cisterns, lavatory-seats, window-sills and as a wall covering, as well as for roofing.

If the Temple House slate pillars had been supplied by Samuel Wyatt, their transport to Bisham could have been relatively simple. Even before the construction of a tramway from Penrhyn Quarry to the coast in 1801, there existed an efficient network of roads linking the quarry to the sea at Port Penrhyn.

From Port Penrhyn a fleet of vessels carried slate around the coast of the British Isles. The Wyatt family had an owning interest in many of these vessels. From London the cargo could be navigated up the Thames by barge.

There is therefore a great deal of circumstantial evidence linking the Bisham slate pillar fence with Samuel Wyatt and Penrhyn Quarry, and dating its construction to around 1790. But one aspect of the pillars' manufacture raises doubts about this. Some of the larger support pillars were clearly cut with circular saws - a technique which was not certainly used before 1805 and only became common from 1840.

One suggestion which unites these two strands of evidence is the possibility that the original fence was erected about 1790, but it had suffered from subsidence in the soft soil around Bisham. The result might have been a second order for Welsh slate around 1840 to rectify the problem.

The fence at Temple House may show evidence of the links between two of Wales's great industrialists, the copper magnate Thomas Williams and Richard Pennant of Penrhyn slate quarry, through the architect Samuel Wyatt. Both shared a common heritage, so what would have been more natural than for Thomas Williams and his architect to display the potential of Welsh slate beside his copper works at Temple Mill?

Background Reading

The Wyatts: an architectural dynasty by John Martin Robinson. Published by Oxford University Press (1979).

'Copper and Slate: Thomas Williams' Slate Pillar Fence at Bisham', by Dafydd Roberts. In The Marlow Historian, vol. 3, p16-21 (2003).

Mrs T. V. Wheeler standing in entrance B of the amphitheatre during its excavation.

Reconstruction of the Caerleon amphitheatre by Alan Sorrell. The amphitheatre is shown as a masonry structure to its full height.

How the amphitheatre may have actually looked. Illustration by Dale Evans (1988) after the reconstruction by R. A. Anderson (1981). Cadw: Welsh Historic Monuments, Crown Copyright.

Re-enactment at Caerleon.

Next to the Roman fortress at Caerleon, near Newport (south Wales), lies the remains of a well-preserved oval amphitheatre, known to local folklore as King Arthur's Round Table. The amphitheatre was excavated in the 1920s by Dr. Mortimer Wheeler, then Director at Amgueddfa Cymru - National Museum Wales. Wheeler's reconstruction of how the amphitheatre may have looked has since been revised as subsequent discoveries have led to a re-think as to how it was constructed.

Securing funds for excavation

Wheeler exploited the connections with King Arthur to drum up sponsorship. The Daily Mail agreed to provide £1,000 for exclusive rights and daily reports on the excavation. The paper eventually trebled its original offer and presented the excavated remains to the then Office of Works (a predecessor of Cadw: Welsh Historic Monuments) as a national monument.

Planning and excavating

In 1926, Wheeler took up the post of Keeper of the London Museum meaning he could not continue his direct involvement with the excavations, but the sponsorship from the Daily Mail made the project binding and urgent, so his wife, Tessa, took over the direction. Every evening a newsworthy story had to be sent to the Daily Mail on the day's discoveries, with 'sensational' headlines such as 'Where Gladiators Fought'.

A structure of earth and masonry

After the excavations were complete and nearly 30,000 tons of soil had been examined and removed from the site, the excavators concluded that the amphitheatre had been constructed around AD 80, several years after the initial foundation of the main fortress at Caerleon. In the report on the findings, published in 1928, the amphitheatre was reconstructed as an earth and masonry structure with the auditorium supported by a bank of earth retained by inner and outer walls of masonry supported and strengthened by buttresses. It was calculated that the original arena wall must have risen to a height of four metres while the external wall must have reached a height of about ten metres. The seats were almost certainly of wood, as no evidence of stone seats was discovered.

In 1939, Alan Sorrell, a well-known painter of archaeological reconstructions shows the amphitheatre built in masonry to its full height.

A new theory

In 1962, George Boon (from the Museum's Department of Archaeology) excavated a small trench in the bank of the amphitheatre, and caused a fundamental re-think of how the superstructure was constructed.

The original surface of the bank was uncovered not far below the turf, this meant that the banks were never higher than they are today. Cut into the surface of the bank were pits, a metre square and deep. Boon concluded that these pits had held large wooden beams forming an openwork timber grandstand. Since this discovery, reconstructions of the amphitheatre have been re-drawn showing its lower part in stone, but with a timber superstructure.

An amphitheatre of similar construction is shown on Trajan's Column at Dobreta, the Roman base on the Romanian side of the Danube bridge.

It has been estimated that the timber grandstand at Caerleon contained 6,000 seats, approximately the full complement of the legion. Events at the amphitheatre, although undoubtedly less bloody, continue to attract large audiences today with exiting re-enactments and other events staged regularly.

Background reading

• Caerleon Roman Fortress by J.K. Night. published by Cadw (2003)
• Isca: The Roman Legionary Fortress at Caerleon, Mon. by G.C. Boon. Published by the National Museum of Wales (1972)
• 'The Roman amphitheatre at Caerleon, Monmothshire' by T.V. -d R.E.M. Wheeler. In Archaeologica vol.78, p.111-218.