George III, 1760-1820. Pattern 1/2 Guinea 1764, London. PROOF. Laureate head right / Crowned shield. 3,92g. Fr. 359; SCBC 3732; W&R 128. NGC PF64 CAMEO (Highest grade). (2124454-038). Very rare. Provenance: H.C. Dangar Collection, Glendining (15 April 1953), 181. Slaney Collection, Spink 3024 (15 May 2003), 9. This exceptionally rare pattern is the work of one of the greatest medallists of the 18th century, Richard Yeo, who became an assistant engraver at the Royal Mint in 1749 and chief engraver in 1775.