The following is the beginning of a chapter from the US Library of Congress on Saudi Arabia's Pre-Islamic Period:
"The bodies of water on either side of the Arabian Peninsula provided relatively easy access to the neighboring river-valley civilizations of the Nile and the Tigris-Euphrates. Once contact was made, trading could begin, and because these civilizations were quite rich, many goods passed between them. The coastal people of Arabia were well-positioned to profit from this trade . . ."