One of them appeared at a recent sale appeared held by St James's Auctions, a gold £20 piece with the half-length portrait of the youthful James VI (who later became James I of England).
It was issued in only two years - 1575 and 1576.
Careful study has demonstrated that some 27 examples exist of both years, although it is just possible that a very few further examples may come to light.
Scotland has long been admired for its high standards of education and this coin was an early example. The Latin legend, in translation, "To spare the humbled and crush the insolent", is a quote from Virgil's Aeneid (VI, 853).
The 1575 example on offer here came to light in 1972, taking £8000 when Sotheby's sold the Bridgewater House collection, which had been unstudied since the 18th century and earlier.
It appeared again at Spink in 1992 when it achieved £25,000, only to appear in a trade fixed price list (Dolphin Coins) in June 1993 asking £45,000. That list recorded only ten examples of the 1575 piece.
It appeared again in 2007 in a private treaty sale at Spink, where it made £75,000. Here at St James's on February 4 the gavel fell to a bid of £130,000 (estimate £110,000-120,000).
The sale of 599 lots achieved a hammer total of £1,319,590, which is equivalent to two thirds of their entire 2012 total.
The buyer's premium was 20%