STOW-ON-THE-WOLD, England—Nearly 50 drawings by Scottish portrait painter Sir Henry Raeburn (1756–1823) have turned up at the Titian Gallery in Stow-on-the-Wold in Gloucestershire, where they are on sale for prices up to £20,000 ($30,000), the Scotsman reports. The drawings come from an album of sketches that belonged to Raeburn's patron, the 13th Lord Gray, and range from images of the Sistine Chapel to portraits after paintings by Sir Anthony van Dyck.

Prior to the discovery, only one or two drawings by Raeburn were known to exist. "I hesitate to use the words Holy Grail, but if it can be proved that these drawings are by Raeburn, they are on the level of a holy relic," said Dr. Duncan Thomson, a former keeper of the Scottish National Portrait Gallery and a Raeburn expert.

Titian Gallery owner Ilona Johnson-Gibbs bought the drawings 12 years ago. They are believed to have been sold by the Gray family in the 1930s. Johnson-Gibbs said the pen-and-ink works were authenticated by Dr. David Mackie, a Raeburn expert at the University of Cambridge who called them the "greatest discovery" he had known.