Fragment of a chart representing the Pacific Ocean
Origin: Portugal
Anonymous (Luis Teixeira)
Date: Sixteenth century (circa 1585)
Material: Illuminated manuscript on parchment
Dimension: Height: 798 mm, Width: 572 mm
MM.05517
Fragment of a chart (world chart) representing part of the Pacific Ocean. It is the oldest known chart displaying isogonic lines (lines of equal magnetic variation). It was believed that this knowledge would allow seafarers to have a more accurate idea of the ship's position. Despite not being signed, the handwriting in the document leads us to believe that the author of the chart is Luís Teixeira (c. 1590). The use of Latin subtitles probably means that the chart was not meant to be used in Portugal.