Esmeraldo de Situ Orbis

Esmeraldo de Situ Orbis is an early modern work on cosmography and Atlantic exploration written by the Portuguese geographer and navigator Duarte Pacheco Pereira.

[7] According to a study by the Portuguese historian Jorge Couto of the University of Lisbon, the work was lost for four centuries due to the confidential nature of its content.

The title was decrypted as: Manuel I considered the nautical, geographical and economic information contained in the work so valuable that he never allowed public access.

The work consists of a detailed account of voyages to Brazil and to the coast of Africa, the main source of Portugal’s lucrative trade in the 15th century.

É achado nela muito e fino brasil com outras muitas cousas de que os navios nestes Reinos vem grandemente povoados.

The manuscript was so rare, in fact, that in 1573 a copy was secretly sent to Philip II of Spain by the Italian spy Giovanni Gesio, under the service of the Spanish ambassador in Lisbon.