Map of the northern Marianas including Saipan, Tinian, Rota and Guam. Bellin apparently conflates these islands with the St. Lazarus archipelago of the Eastern Philippines, discovered by Magellan in the same historic voyage. For centuries, Guam was a strategic port of call in the Spanish Galleon trade, and an inset map shows the island in good detail. The centrally radiating rhumb lines make this an attractive small map