This medal was commissioned by the Royal Society in recognition of Captain Cook's services to science and exploration. During a distinguished Naval career, he developed skills in surveying and in astronomy, and was an excellent choice for the expedition to the Pacific, to make precise observations of the transit of Venus in 1769, giving the necessary data for mapping the solar system.  His three voyages over the decade up till his death in Hawaii in 1779 led to his charting many of the coastlines around the Pacific with remarkable accuracy, and he pioneered the use of fresh fruit to combat the scurvy which tended to exact a severe toll among the ship's crew.  This is one of the small number of examples of this medal struck in gold, for presentation to royalty.