Drawings by Leonardo da Vinci will go on public display in Aberystwyth next year, as part of Prince Charles's 60th birthday celebrations.
The equestrian monument sketches were drawn in about 1508
The 10 works from the Royal Collection will form part of a touring exhibition which will visit other parts of the UK.
The tour will include only one Welsh venue, the National Library of Wales, from November 2008 for three months.
The Royal Collection Trust (RCT) said the drawings were the "richest" and "wide ranging" of any artist.
The drawings are normally kept at Windsor Castle.
They have been in the Royal Collection since the 17th Century and were probably acquired during the reign of Charles II.
The RCT said the exhibition had been selected to demonstrate the "extraordinary scope of his (Da Vinci's) interests", and includes studies for painting, sculpture and architecture.
The drawings were displayed at Swansea's Glynn Vivian Art Gallery for two months in 2002 and attracted a record 30,000 visitors.
They were also seen by 169,000 visitors in Cardiff during a touring exhibition to celebrate the Queen's 80th birthday.
The Aberystwyth exhibition will run from 8 November, 2008, until 7 February, 2009.
The Prince of Wales was celebrating his 59th birthday on Wednesday.