Cristóvão de Mendonça (Mourão, 1475 – Ormus, 1532)[1] was a Portuguese noble and explorer who was active in South East Asia in the 16th century.

Mendonça is named by Barros as the captain of a ship that left Lisbon in 1519 and, after arriving at Goa, as having been given instructions to search for Pliny's legendary Isles of Gold (Chryse), said to lie to "beyond Sumatra":At the end of June of the year 1520, a ship arrived that had departed the Kingdom that year, the Captain and Pilot being Pedro Eanes, nicknamed the Frenchman, who being a diligent man and one well versed in matters of the sea, King Manuel had entrusted with letters for Diogo Lopez concerning matters of service.

[5] Barros promises to return to the topic of the voyage to the Isles of Gold, and subsequently does so, relating how Mendonça was diverted from the quest by the requirement to assist with the building and defence of a fort at Pedir in the territory of the Sumatran principality of Pacem (Pasai).

[9]The belief in the Isles of Gold/Ilhas do Ouro derived from the legendary Suvarnadvipa and (Suvarnabhumi) mentioned in ancient Indian literature and incorporated into Graeco-Roman geography as the Islands of Gold and Silver (Chryse and Argyre) and the Golden Chersonese (Chersonesus Aurea).

[13] McIntyre pointed out that any such Portuguese expedition would likely have remained secret, because it might have violated the Treaty of Tordesillas, under which Portugal agreed that Spain would have exclusive rights to exploration in the Pacific.

[20] Commenting on McIntyre's theory in 1984, Captain A. Ariel[21] suggested it was extremely unlikely any sixteenth century mariner would have taken a voyage southwards down Australia's eastern coast, through uncharted dangerous waters and against prevailing winds, on the assumption Magellan was sailing westwards, in southern latitudes, against the Roaring Forties.