The Greeks were aware that the sea brings together material goods, freedom, knowledge and readiness for action. This knowledge guided Greeks at every turn of their history to perform glorious deeds in peace and in time of war. Continuously increasing archaeological data proves beyond the shadow of a doubt the importance and influence of navigation on the development of the prehistoric civilization of Greece; that of the Neolithic period, the Cycladic, the Early Helladic II, the Minoan and the Mycenaean civilization. Research done on navigation in the prehistoric age lacks written sources. The Homeric poems, documents connecting prehistory to history, describe the naval life of the Achaeans, while Linear B, the texts of the Mycenaean period ,are succinct in relevant information. Shipwrecks are also an important source, since their cargo can supply research with valuable information. Pictures of ships are found on Cycladic pottery and other art media, like wall paintings, Minoan seals etc. while the ships decorating Mycenaean pottery are briefly sketched. Ship-effigies made of clay or metal come from tombs of all periods. The fact that obsidian, volcanic glass, has been found in all the Neolithic settlements in Macedonia, Thessaly and the Peloponnese, is evidence of the existence of trade-ships, since this material could only come for the island of Melos. The sailing boats carved on Minoan seals probably depict those trade-ships in which the Cretans travelled all over the then known world. The theory of the thalassocracy (sea rule) of Crete is based on the fact that the Minoan coastal settlements were not fortified and also on the abundance of representations of ships carved on seals. Judging, however, from the evidence that pottery offers, we come to wonder whether this thalassocracy (sea rule) belonged to the Mycenaeans rather than to the Minoans. Minoan pottery has been found in Egypt, while Mycenaean pottery prevails from the eastern coast of the Mediterranean Sea to southern Italy. The importance the sea gained in the Cycladic era is further underlined by the role ships play in the religion of the time as an object lidea; ships’ effigies have been found in tombs, a ship is included in the religious scene painted on the famous sarcophagus of Agia Triada and similar scenes with the indispensable ship-symbol decorate Minoan and Mycenaean jewelry. The most significant representation, however, is the marine wall-painting from Thera Island, telling the tale of a special kind of ritual. The impressive ships depicted there, symbols of power, cannot belong to any other but to a seafaring civilization going back centuries.