Note 254 — Chapter VII · Globes of the Second Quarter of the Sixteenth Century

He seems to have produced nothing of special importance in his capacity as “Historicus Regius,” giving, however, some attention to the subjects of heraldry, and genealogy. The question of the determination of longitude interested him, and there is still preserved, in the Royal Library of Madrid, his manuscript bearing the title “Libro de las longitudes y manera que hasta ago se ha tenido en el arte de navegar con sus demonstraciones y examplos.” At the time of his death there was also left a paper in manuscript, treating of the subject of longitude, which probably contains a summary of suggestions made to the Junta in Sevilla in the year 1536 “sobre la orden que se ha tenido en el dar de la longitud.”