Refer to the passage below and then answer the question afterwards in the same language as the passage:

Passage: On 8 July 1497 Vasco da Gama led a fleet of four ships with a crew of 170 men from Lisbon. The distance traveled in the journey around Africa to India and back was greater than around the equator. The navigators included Portugal's most experienced, Pero de Alenquer, Pedro Escobar, João de Coimbra, and Afonso Gonçalves. It is not known for certain how many people were in each ship's crew but approximately 55 returned, and two ships were lost.  Two of the vessels were carracks, newly built for the voyage; the others were a caravel and a supply boat.The four ships were:

Question: What year did the Vasco da Gama lead four ships with 170 members in crew?
1497