Context: The islands were first sighted in 1506 by Portuguese explorer Tristão da Cunha; rough seas prevented a landing. He named the main island after himself, Ilha de Tristão da Cunha, which was anglicised from its earliest mention on British Admiralty charts to Tristan da Cunha Island. Some sources state that the Portuguese made the first landing in 1520, when the Lás Rafael captained by Ruy Vaz Pereira called at Tristan for water. The first undisputed landing was made in 1643 by the crew of the Heemstede, captained by Claes Gerritsz Bierenbroodspot.

Question: in what year were the islands first sighted?
Answer: 1506

Question: what was the name of the explorer that sighted them?
Answer: Tristão da Cunha

Question: who was the main island named after?
Answer: Portuguese explorer Tristão da Cunha

Question: what year was it said the first island landing was made?
Answer: 1520

Question: Who first sighted the Islands in 1643?
Answer: Unanswerable

Question: Who made the first undisputed landing in 1506?
Answer: Unanswerable

Question: Who was the captain of the Tristan da Cunha?
Answer: Unanswerable

Question: When do some sources say the British made the first landing?
Answer: Unanswerable

Question: By who was the Las Gerritsz captained?
Answer: Unanswerable