At the turn of the 16th century, a revolution in military affairs at sea began, which took a long time to prepare, but, once it began, it became surprisingly fast. Driving force: gunpowder. The main agents are galleys (long low boats powered mainly by oars) and galleons (heavy sailing ships with square weapons). Suddenly, Europe, previously at the same technological level as India and China, began to dominate the waters. They crossed the Atlantic, reached America and became world powers.