(The meaning of the 'esmeraldo' in the title has been much speculated. Among the proposals, it is a reference to the emerald green of the sea; that it is an anagram combining the names 'Emmanuel' (for King Manuel I of Portugal) and 'Eduardus' (of Duarte Pacheco), that "Esmeralda" might have been the name (or nickname) of the ship Duarte Pacheco sailed to India, that it is a corruption of the Spanish word "esmerado" (meaning "guide"), that in Malayalam, an emerald gemstone is known as "pache" or "pachec", and thus "Esmeraldo" is a pun on his own name (thus, "Pacheco's De Situ Orbis").