No doubt he ventured at first as a fisherman, having learnt the elements of seacraft in creeks and lagoons. Men may have navigated boats upon the Levantine lake before the refilling of the Mediterranean by the Atlantic waters. The canoe was an integral part of the heliolithic culture, it drifted with that culture upon the warm waters of the earth from the Mediterranean to (at last) America. There were not only canoes, but Sumerian boats and ships upon the Euphrates and Tigris, when these rivers in 7000 B.C. fell by separate mouths into the Persian Gulf. The Sumerian city of Eridu, which stood at the head of the Persian Gulf (from which it is now separated by a hundred and thirty miles of alluvium[121]), had ships upon the sea then. We also find evidence of a fully developed sea life six thousand years ago at the eastern end of the Mediterranean, and possibly at that time there were already canoes on the seas among the islands of the nearer East Indies. There are pre-dynastic Neolithic Egyptian representations of Nile ships of a fair size, capable of carrying elephants.[122] Very soon the seafaring men must have realized the peculiar freedom and opportunities the ship gave them. They could get away to islands; no chief nor king could pursue a boat or ship with any certainty; every captain was a king. The seamen would find it easy to make nests upon islands and in strong positions on the mainland. There they could harbour, there they could carry on a certain agriculture and fishery; but their speciality and their main business was, of course, the expedition across the sea. That was not usually a trading expedition; it was much more frequently a piratical raid. From what we know of mankind, we are bound to conclude that the first sailors plundered when they could, and traded when they had to. [Illustration: Boats on the Nile, about 2500 B.C. [From Torr’s “Ancient Ships”.]]