Work is still going on to understand the history and sigificance of the faded inscription on the 9th Century monument, Pillar of Eliseg, near Llangollen.

And one of the best ways to examine the writing has been using night photography which was the focus of BBC TV series, Hidden Histories, following the everyday work of Royal Commission on the Ancient and Historical Monuments of Wales.

One episode followed Royal Commission photographer Iain Wright as he works at night with artificial lighting to try to recover any fragments of the eroded inscription on the pillar.

The inscription told the story of the early medieval Welsh leader Eliseg on the pillar put up in his memory near Llangollen.

In the 9th Century, a cross was erected at Vallé Crucis to commemorate an early medieval leader, Eliseg (or Elisedd). Only the shaft of the cross remains and its inscription, which was already almost illegible when the antiquary Edward Lhuyd tried to transcribe it in 1696, has disappeared.

Eliseg's great-grandson, Cyngen (died 854), commemorated the achievements of his ancestor by raising the cross and written in Latin in 31 horizontal lines, the inscription was broken into paragraphs separated by small crosses.

It glorified Eliseg and Cyngen, proclaiming their lineage from the Roman Emperor Magnus Maximus and his son Vortigern (or Gwrtheyrn), and asserted that Eliseg drove the English from the area after they had laid this borderland waste for nine years.

In 1987, the Royal Commission began to record early medieval inscribed stones for a revised edition of Early Christian Monuments of Wales.

Working at night with artificial light projected onto the stone was decided as the most effective approach. The new photography could only hint at where the original lines of text once were, but it recorded the 18th Century inscription describing the re-erection of the cross before it, too, is weathered beyond recognition.