Fact Finder - History

John Hadley and Thomas Godfrey independently invented the sextant, a device that allowed sailors to measure the angle between a celestial object and the horizon with extreme precision. Before the sextant, navigation at sea was often guesswork. This invention allowed mariners to determine their latitude exactly, even on a moving ship. Combined with the marine chronometer, it made long-distance global trade and exploration safe and predictable, cementing the era of global naval power and European maritime expansion.