Damião de Góis
On diplomatic mission to Antwerp in his twenties, Góis acquired and translated into Latin an account of Matthew's journey to Portugal and his interactions with the Portuguese King. This translation was published without Góis's knowledge or permission as Embassy of the Great Emperor of the Indians, Prester John, to Manoel, King of Lusitania [Portugal], now also known as the Legatio.
The Legatio was published in 1532 on the heels of the recent Portuguese embassy to Abyssinia (1520-1526) (led by Diogo Lopes de Sequeira and recorded by Francisco Álvares). As Silverberg (p. 299) points out, Góis's text, which only covered Matthew's journey to Portgual, should have been obselete now that Álvares had returned to Portgual from Ethiopia, but the account of Álvares's journey would not be published for another eight years.
Damião's Legatio was an important early modern source on Ethiopian Christianity, which positioned these Christians (and thus the kingdom of Prester John) as schismatic heretics in need of conversion. The account was quickly translated into English by John More.