William Marsden (16 November 1754, Verval, County Wicklow – 6 October 1836, London) was an Irish orientalist, numismatist, and linguist who served as First Secretary to the Admiralty during years of conflict with France, and commented The Travels of Marco Polo (1818), with annotations that brought some important clarification on early Southeast Asia.
Joining the East India Company at sixteen years of age, he was sent to Benkulen, Sumatra, in 1771, where he spent eight years and acquired a vast knowledge of the Malay language.
He was the first scientist to identify Marco Polo's Ziamba as 'Tsiampa, Siampa, Ciampa, or Champa, situated to the southward of Kochinchina' (1).
1) 交趾支那 (transliterad Tchen-tching by first European explorers, Jaozhi Zhina) in Chinese sources, Cochinchina (កូសាំងស៊ីន) is the old name given to the lands south of the Gianh River, an area often contested by modern Cambodia and Vietnam. The origin of the term is also contested, some sources attributing it to the Portuguese (Ko-Chen-China, 'the Cochin of China', to distinguish it from the Indian Cochin), while some linguists have offered the poetic etymology of 'Given Daughter of China'.