In the fifteenth and sixteenth centuries, Iberian shipwrights developed vessels suited to long ocean voyages: the lateen-rigged caravel, agile and able to sail close to the wind, followed by the larger carrack and galleon built to carry cargo and guns across open seas. These ships were combined with navigational tools including the magnetic compass, the astrolabe and quadrant for measuring latitude, and printed sailing charts and rutters. Together they made sustained voyaging across the Atlantic and into the Indian Ocean practical. Portuguese and Spanish crews used them to open new sea routes.
They underwrote the maritime empires and the global trade in goods, people and silver that founded and enlarged port cities across four continents, reorienting urban networks toward oceanic commerce.