A collection of early Christian carved stones have gone back on display following specialist conservation work which revealed they may be the oldest Christian monuments in Britain.

The work in Edinburgh included detailed cleaning of the stones' intricate carved designs, revealing previously undiscovered details. They have now been returned to their home of Dumfries and Galloway.

The stones were also laser scanned to capture a surface map, as well as drawn and photographed by The Royal Commission on the Ancient and Historical Monuments of Scotland.

The grassy knoll of Kirkmadrine was once an important monastic centre. It is home to some of Scotland's earliest Christian sculpture, including three tall stones with Latin inscriptions carved around AD 550 to 600. Probably recycled standing stones, these remarkable carved stones represent a transition from pagan to Christian worship.

The collection also includes some later carvings, commissioned by the Gaelic speakers who emerged as rulers of this area between about AD 800 and 1100.

Research commissioned while the stones were off display has shown it is likely the religious community at Kirkmadrine was just as important as the later monastery at Whithorn. The three earliest stones on display at Kirkmadrine have Latin carvings and feature the powerful Chi Rho symbol - originally a code among early Christians - which uses the Greek letters for Christ. The stones also feature the names of individuals who are thought to have been bishops based at a religious centre at Kirkmadrine.

The Kirkmadrine project has highlighted just how important this site is, with new research increasing the understanding and significance of this particular area of Scotland in the 6th and 7th centuries.

Richard Welander, Head of Collections at Historic Scotland, said:

"The Kirkmadrine stones can truly lay claim to being one of Britain's archaeological 'hidden gems'. At the end of an isolated country lane in the beautiful landscape of the Rhinns of Galloway, anybody who takes the time to find this remote chapel site will be rewarded by the discovery of some of the oldest surviving Christian monuments in Britain. Inscribed with early Christian symbols, the stones date from a time when the tectonic plates of early medieval Scotland were on the move, where paganism met Celtic Christianity for the first time.