João de Barros (1496–October 20, 1570), called the Portuguese Livy, is one of the first great Portuguese historians, most famous for his Décadas da Ásia ("Decades of Asia"), a history of the Portuguese in India and Asia.
The pestilence of 1530 drove him from Lisbon to his country house near Pombal, and there he finished a moral dialogue, Rho pica Pneuma, which met with the applause of the Juan Luís Vives. On his return to Lisbon in 1532 the king appointed Barros factor of the India and Mina House—positions of great responsibility and importance at a time when Lisbon was the European center for the trade of the East. Barros proved a good administrator, displaying great industry and a disinterestedness rare in that age, with the result that he made but little money where his predecessors had amassed fortunes. At this time, John III, wishing to attract settlers to Brazil, divided it up into captaincies and gave that of Maranhão to Barros, who, with two partners, prepared an armada of ten vessels, carrying nine hundred men each, which set sail in 1539. Owing to the ignorance of the pilots, the whole fleet was shipwrecked, which entailed serious financial loss to Barros. As a gesture of goodwill, Barros subsequently paid the debts of those who had perished in the expedition.
During these years he had continued his studies in his leisure hours, and shortly after the Brazilian disaster he offered to write a history of the Portuguese in India, the Décadas da Ásia, which the king accepted. He began work forthwith, but, before printing the first part, he published a Portuguese grammar (1539) and some further moral Dialogues.
His Decades contain the early history of the Portuguese in India and Asia and reveal careful study of Eastern historians and geographers, as well as of the records of his own country. They are distinguished by clearness of exposition and orderly arrangement. They are also lively accounts, for example describing the king of Viantana's killing of the Portuguese ambassadors to Malacca with boiling water and then throwing their bodies to the dogs.
Diogo de Couto continued the Décadas, adding nine more, and a modern edition of the whole appeared in Lisbon in 14 vols. in 1778—1788 as Da Asia de João de Barros, dos feitos que os Portuguezes fizeram no descubrimento e conquista dos mares e terras do Oriente. The edition is accompanied by a volume containing a life of Barros by the historian Manoel Severim de Faria and a copious index of all the Decades.