The phenomenon of colonization is one that has occurred around the globe and across time. Various ancient and medieval polities established colonies – such as the Phoenicians, Babylonians, Persians, Greeks, Romans, Han Chinese, and Arabs. The High Middle Ages saw colonising Europeans moving west, north, east and south. The medieval Crusader states in the Levant exemplify some colonial features similar to those of colonies in the ancient world.
A new phase of European colonialism began with the "Age of Discovery", led by the Portuguese, who became increasingly expansionist following the conquest of Ceuta in 1415. Portugal aimed to control navigation through the Strait of Gibraltar, to spread Christianity, to amass wealth and plunder, and to suppress predation on Portuguese populations by Barbary pirates (who operated as part of a longstanding African slave tradeat that point a minor trade, one the Portuguese would soon reverse and surpass). Around 1450 the Portuguese developed a lighter ship, the caravel based on North African fishing boats. Caravels could sail further and faster than previous vessels, were highly maneuverable, and could sail into the wind.