Between 1492 and 1504, Italian explorer Christopher Columbus led four Spanish transatlantic maritime expeditions of discovery to the Americas. These voyages led to the widespread knowledge of the New World. This breakthrough inaugurated the period known as the Age of Discovery, which saw the colonization of the Americas, a related biological exchange, and trans-Atlantic trade. These events, the effects and consequences of which persist to the present, are often cited as the beginning of the modern era.