Which European country lead the way in overseas exploration?

Portugal was the leading European country in overseas exploration during the Age of Discovery in the 15th and 16th centuries. Under the patronage of Prince Henry the Navigator, Portuguese explorers mapped much of the West African coast and were the first Europeans to reach India by sea, with Vasco da Gama's voyage in 1498. Their advancements in navigation, shipbuilding, and cartography laid the groundwork for subsequent explorations by other European powers.