The map is derived from a two-sheet map by Fernando Alvarez Secco which was published by Michele Tramezzino in 1561. This is an early issue of the second of two plates by Ortelius of Portugal. There are only subtle differences in engraving between them. Van den Broecke, M. #27, state 1; ‘Cartografia Impressa dos Seculos XVI e XVII Imagens de Portugal …’ Exhibition Catalogue no. 22; Koeman Ort no. 8 (not realising the two plates existed); ‘Olhar o Mundo ler o Territorio’ Exhibition Catalogue p. 144.