<Li> 1460--Death of Prince Henry, the Navigator . His systematic mapping of the Atlantic, reached 8 ° N on the African Coast and 40 ° W in the Atlantic (Sargasso Sea) in his lifetime . </Li> <Li> 1461--Diogo Gomes and António de Noli discovered more of the Cape Verde Islands . </Li> <Li> 1461--Diogo Afonso discovered the western islands of the Cabo Verde group . </Li> <Li> 1471--João de Santarém and Pedro Escobar crossed the Equator . The southern hemisphere was discovered, requiring the sailor to use a new constellation to guide them, the Southern Cross . The discovery of the islands of São Tome and Principe is also attributed to these same sailors . </Li>

Why did china give up its dominance of the seas after 1435