The Age of Discovery is the time period in ocean exploration history when the initiative to explore the remaining undiscovered land masses and trade routes occurred. Starting in the fifteenth century and ending in the eighteenth century, it was a massive period of exploration and colonization to expand power and resources for many of the countries in western Europe, like the Spanish, British, Portuguese and French. Several technological advancements relating to sea travel spurred this phenomenon, like improved sail systems, larger ships and guidance systems like a mariner's compass.