Given the task definition, example input & output, solve the new input case.
This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Example: Passage: The French and Indian War (17541763) was the North American theater of the worldwide Seven Years' War. The war was fought between the colonies of British America and New France, with both sides supported by military units from their parent countries of Great Britain and France, as well as Native American allies. At the start of the war, the French North American colonies had a population of roughly 60,000 European settlers, compared with 2 million in the British North American colonies. The outnumbered French particularly depended on the Indians. Long in conflict, the metropole nations declared war on each other in 1756, escalating the war from a regional affair into an intercontinental conflict.
Output: When was the French and Indian War?
This question is based on the following sentence in the passage- The French and Indian War (17541763) was the North American theater of the worldwide Seven Years' War. It is a common convention to write (start year-end year) beside a historical event to understand when the event happened. You can ask questions like this one about dates, years, other numerals, persons, locations, noun phrases, verb phrases, adjectives, clauses etc. which exist in the paragraph.

New input case for you: Most historical accounts state that the island was discovered on 21 May 1502 by the Galician navigator Joao da Nova sailing at the service of Portugal, and that he named it "Santa Helena" after Helena of Constantinople. Another theory holds that the island found by da Nova was actually Tristan da Cunha, 2,430 kilometres (1,510 mi) to the south, and that Saint Helena was discovered by some of the ships attached to the squadron of Estevao da Gama expedition on 30 July 1503 (as reported in the account of clerk Thome Lopes). However, a paper published in 2015 reviewed the discovery date and dismissed the 18 August as too late for da Nova to make a discovery and then return to Lisbon by 11 September 1502, whether he sailed from St Helena or Tristan da Cunha. It demonstrates the 21 May is probably a Protestant rather than Catholic or Orthodox feast-day, first quoted in 1596 by Jan Huyghen van Linschoten, who was probably mistaken because the island was discovered several decades before the Reformation and start of Protestantism. The alternative discovery date of 3 May, the Catholic feast-day for the finding of the True Cross by Saint Helena in Jerusalem, quoted by Odoardo Duarte Lopes and Sir Thomas Herbert is suggested as being historically more credible.
Output:
What date was the island discovered on?