Magellan, has definitely seen the island as he passed for the first time in the strait, Pigafetta, while speaking about the desertion of Sab Antonio cites in his famous book, s:The First Voyage Round the World/Pigafetta's Account of Magellan's Voyage (Chap.79), that in order to alert the crew of the ship if they ever try to get back:
"This manner of acting had been ordained by the captain from the commencement, in order to effect the junction of any ship which might be separated from the others. So the people of the said ship did what the captain had commanded them, and more, for they set two ensigns with letters; one of the ensigns was placed on a small hill at the first bay, the other on an islet in the third bay, where there were many sea wolves and large birds
