Prince Henry was born in 1394 as the third son of King John I (King Joao I) of Portugal. At the age of 21, in 1415, Prince Henry commanded a military force that captured the Muslim outpost of Ceuta, located on the south side of the Strait of Gibraltar.
Three years later, Prince Henry founded his Institute at Sagres on the southwestern-most point of Portugal, Cape Saint Vincent - a place ancient geographers referred to as the western edge of the earth. The institute, best described as a fifteenth century research and development facility, included libraries, an astronomical observatory, ship-building facilities, a chapel, and housing for staff.
The institute was designed to teach navigational techniques to Portuguese sailors, to collect and disseminate geographical information about the world, to invent and improve navigational and seafaring equipment, to sponsor expeditions, and to spread Christianity around the world - and perhaps even to find Prester John. Prince Henry brought together some of the leading geographers, cartographers, astronomers, and mathematicians from throughout Europe to work at the institute.
Although Prince Henry never sailed on any of his expeditions and rarely left Portugal, he became known as Prince Henry the Navigator.
The institute's primary exploration goal was to explore the western coast of Africa to locate a route to Asia. A new type of ship, called a caravel was developed at Sagres. It was fast and was much more maneuverable than prior types of boats and though they were small, they were quite functional. Two of Christopher Columbus' ships, the Nina and the Pinta were caravels (the Santa Maria was a carrack.)
Caravels were dispatched south along the western coast of Africa. Unfortunately, a major obstacle along the African route was Cape Bojador, southeast of the Canary Islands (located in Western Sahara). European sailors were afraid of the cape, for supposedly to its south lay monsters and insurmountable evils.
Prince Henry sent fifteen expeditions to navigate south of the cape from 1424 to 1434 but each returned with it's captain giving excuses and apologies for not having passed the dreaded Cape Bojador. Finally, in 1434 Prince Henry sent Captain Gil Eannes (who had previously attempted the Cape Bojador voyage) south; this time, Captain Eannes sailed to the west prior to reaching the cape and then headed eastward once passing the cape. Thus, none of his crew saw the dreadful cape and it had been successfully passed, without catastrophe befalling the ship.
Following the successful navigation south of Cape Bojador, exploration of the African coast continued.
In 1441, Prince Henry's caravels reached Cape Blanc (the cape where Mauritania and Western Sahara meet). In 1444 a dark period of history began when Captain Eannes brought the first boatload of 200 slaves to Portugal. In 1446, Portuguese ships reached the mouth of the Gambia River.
In 1460 Prince Henry the Navigator died but work continued at Sagres under the direction of Henry's nephew, King John II of Portugal. The institute's expeditions continued to venture south and then rounded the Cape of Good Hope and sailed to the east and throughout Asia over the next few decades.