Christopher Columbus (1451-1506), Italian explorer. Columbus went to sea at the age of 10 but by age 22 had started an apprenticeship as a business agent for several important Geonoese families. Based on flawed assumptions of geography and even worse mathematics, Columbus calculated that a westward route from the Canary Islands to Japan would be a mere 3700km (as opposed to the true 19600km), and proposed an expedition to prove this. He eventually secured the support of Queen Isabella I of Spain and in 1492 arrived in the Bahamas, Hispaniola and Cuba. Over a further three voyages he discovered much of the Caribbean and the coast of the southern Gulf of Mexico.