The greatest and most famous lighthouse in history was, of course one of the 7 Wonders of the World, the infamous Lighthouse at Alexandria, in ancient Egypt.
And the ancient Latins — knowing all about and in awe of the amazing lighthouse- referred to it by the title of the man who built it which was, of course, the King of Egypt. And they called their Kings, Pharaohs!
Pharaoh — yes, the same Pharaoh featured in the Old Testament who enslaved the Jews and thus of course gave them the holiday of Passover — in Spanish is written faraón. Thus, giving rise to the word faro for lighthouse.