Prince tours the ancient and digital on day two of tour
Prince Charles learned about the old and the hi-tech new on the second day of his summer tour of Wales.
He and the Duchess of Cornwall visited a chapel with some of the oldest Celtic crosses in Wales and toured a factory making the Raspberry Pi computer.
Later they hosted a reception at their Carmarthenshire home to mark 100 years since the birth of poet Dylan Thomas.
This year's tour is "celebrating Wales, past, present and future".
The royal couple started their annual summer tour on Monday visiting Carmarthenshire and Pembrokeshire.
On Tuesday, they began the day in bright sunshine at the newly restored Galilee Chapel at St Illtud's Church in Llantwit Major, Vale of Glamorgan.
The 13th Century chapel holds one of the most important collections of Celtic Christian stones in the UK but was a roofless ruin until it was transformed in to a visitor centre in an £850,000 project.
The church was founded by the Welsh monk Illtud and dates back to the year 500 and is one of the earliest centres of Christian learning in Wales.
The chapel now provides a new home for Celtic crosses which date back more than 1,000 years.
One of the Celtic crosses is the Abbot Samson's Pillar Cross, sometimes known as the King Stone, and is believed to be one of the oldest known inscribed Christian stones in Great Britain.
The rector of Llantwit Major, Rev Huw Butler, said: "It was such a beautiful day. The prince was very interested in the history of the stones.
"Thanks to the restoration project they are now being displayed properly and have been placed so that visitors can walk all around them to see them from all angles."
The royal couple then went on to the Edwardian Dyffryn House and gardens to celebrate the 25th anniversary of the Welsh Historic Gardens Trust, of which the prince is patron.
Prince Charles also launched the Welsh Historic Gardens Trust Small Grants Scheme, which aims to provide at least £25,000 in small grants to garden projects throughout Wales.
Since the last royal visit to the gardens in 2007, major renovation and conservation work has been carried out at the site with funding from the Heritage Lottery Fund.
The royal couple planted a tree dahlia in the exotics bed of the gardens to commemorate 100 years since the dahlia trials, when 7,000 dahlias were planted in the gardens.
From there, the prince travelled to Sony's factory at Pencoed, near Bridgend, to see how the credit card-sized Raspberry Pi computer is manufactured.
The site has made more than two million units of the tiny computer, developed to encourage young people's interest in computer science and coding, have been made at the site since August 2012.
Prince Charles also met some of the entrepreneurs whose businesses are based within the factory.
Meanwhile, the duchess visited the Welsh National War Memorial in Cathays Park, Cardiff, as part of a campaign to highlight war memorials at risk of damage or theft.
She also met staff and patients at the University of Wales Hospital, Cardiff, biomechanics and bioengineering centre to learn more about the work done by Arthritis Research UK there.
The couple ended the day by hosting a reception at their Llwynywermod estate in to mark 100 years since the birth of Dylan Thomas.
The prince is royal patron of the Dylan Thomas 100 Festival, which has organised a series of events celebrating the poet's life and work throughout 2014.
Thursday, 3 July
- The royal couple will lay a wreath at the Welsh national mining memorial in Senghenydd before touring and officially opening Aber Valley Heritage Museum
- The duchess visits Usk to celebrate the 50th anniversary of the Britain in Bloom competition
- The prince will see restoration and development plans during a visit to Llwyn Celyn farmstead, Crucorney Fawr
- The prince will visit the family-run Welsh Farmhouse Apple Juice company in Crickhowell, Powys
Friday, 4 July
- The prince visits the Plough Chapel in Brecon