Why did the Admiral circumnavigate Africa?

Directions: Read the following passage and answer the questions that follows.

Before telling how the ancients got to know that part of the world with which they finally became acquainted when the Roman Empire was at its greatest extent, it is as well to get some idea of the successive stages of their knowledge, leaving for the next chapter the story of how that knowledge was obtained. As in most branches of organised knowledge, it is to the Greeks that we owe our association with ancient views of this subject. In the early stages, they possibly learned something from the Phœnicians, who were the great traders and sailors of ancient times and who coasted along the Mediterranean, passed through the Straits of Gibraltar, and traded with the British Isles, which they visited for the tin found in Cornwall. It is even said that one of their admirals, at the command of Necho, King of Egypt, circumnavigated Africa, for Herodotus reports that on the homeward voyage, the sun set in the sea on the right hand. But the Phœnicians kept their geographical knowledge to themselves as a trade secret, and the Greeks learned, but little from them.