Because the blacks needed a period of probation and instruction. A period is long enough for the black to have forgotten something of the condition as a slave.
Answer:
The astrolabe was the most important invention of the Age of Exploration, as seen through the facts that it could determine local time and latitude, measure the angles of stars, and locate the positions of the Sun, Moon, planets, and more components of astronomy.
He was 58 at the time of his marriage.
I would say that Christopher Columbus was influenced by the travels of Marco Polo.
He was greatly inspired by his travels and wanted to become as famous as Polo was as an explorer, and eventually, he did follow in his footsteps. Polo's travels changed the European perception of the Asian world, and as you know, Columbus also wanted to go to Asia, but he ended up in America.