You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Tristan_da_Cunha

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

1520