(1) Prince Henry led the way in sponsoring exploration for Portugal, a small nation next to Spain. First, Prince Henry’s navigators discovered and claimed the Madeira and Azores islands to the west and southwest of Portugal. By 1415, Portugal had expanded into Muslim North Africa, seizing the port of Ceuta on the North African coast. (2) Prince Henry saw great promise in Africa. The Portuguese could convert Africans - most of whom practiced tribal religions - to Christianity. He also believed that in Africa he would find the sources of riches the Muslim traders controlled. (3) Finally, Prince Henry hoped to find an easier way to reach Asia, which meant going around Africa. The Portuguese felt that with their expert knowledge and technology, they could accomplish this feat. At Sagres, in southern Portugal. Henry gothered scientists, cartographers, or mapmakers, and other experts. They redesigned ships, prepared maps, and trained captains and crews for long voyages. Henry’s ships then slowly worked their way south to explore the western coast of Africa. (4) Henry died in 1460, but the Portuguese continued their quest. In 1488. Bartholomeu Dias rounded the southern tip of Africa. Despite the turbulent seas around it, the tip became known as the Cape of Good Hope because it opened the way for a sea route to Asia.
Which word can we use to replace the word because in Paragraph (4)?