Mare Orientale: The Eastern Sea in the west - Discovery and nomenclature

The history of the discovery of the great impact feature on the Moon known as the Orientale basin is traced from its partial recognition in the eighteenth century to its identification and naming by the German astronomer Julius Heinrich Georg Franz sometime before 1906, through to Hugh Percival Wilkins who made the first detailed visual study in 1937, and the observations of Samuel Morris Green in the period 1938-1939. Some account is also given of later developments in the saga of its nomenclature and the eventual recognition of its true physical character.