The author undertakes a study of the concept of island in the work of Thucydides and his contemporaries. The problem is how and to what extent Athens' «sea» orientation of the 5th с ВС affected the psychology of the Athenian community and the Athenian's views of their geo-political position. Aristophanes, who was especially sensitive to the mood of the Athenian community during the Peloponnesian War, regarded the islands as a part of the Athenian sea power (arche), «is-land» thus being for him synonymous with «polis-member of the Athenian Empire». As for Thucydides, when he speaks of war and political realities of his time, political geography sup-plants physical one. The peninsula of Pallene is treated by him as an island, and Sicily is de-scribed as if it were a continent. For Thucydides, as well as for other Athenian writers of the 40 5th and 4th с. ВС. «islanders» were primarily inhabitants of the Cyclades constituting the fifth tribute area of the Athenian arche. In a wider sense the word applies to all the islands (and not only islands) allied with Athens, i.e. all the subjects of the arche. In this respect Aris-tophanes goes even further than Thucydides: for him, «islander» is a synonym for «ally» in general, and Athens is one of the «islands». The anonymous (Pseudo-Xenophon's) Athenaion Politeia (contemporary with Thucydides), discussing advantages and disadvantages of insular and continental location of a state, inevitably treats Athens and Piraeus (connected by the Long Walls) as a sort of island. How can this «imperial» «geo-political» view of the islands in Thucydides and his contem-poraries be accounted for? One may suppose that Athenians had long envied islanders, natu-rally protected against invasions from land. It would be enough to recall their struggle with Megara for Salamis or their hatred for the Aeginians, which made them adopt Themistocles' proposal and build a big navy (Herodotus, Thucydides). The very sight of prosperous Aegina protected by the sea and very well seen from the Athenian Acropolis could not but urge the Athenians to take decisive measures. As soon as Athens became the leading sea power in the Aegeis, the task of subjecting the islands became the first item to be put on the agenda. When it was, the allied islanders had to submit to Athens, sometimes not on quite voluntary lines. Obviously, Thucydides and the contemporary authors (Aristophanes, Pseudo-Xenophon), as well as common Athenians, came to see the inhabitants of the Archipelago primarily as sub-jects of the Athenian Empire, and thus the word «island», besides its common geographical meaning, acquired a geo-political (or politico-geographical) connotation. The author concludes that in democratic Athens of the 5th с. ВС its notional geographical self-positioning, i.e. the view of Athens as of a sort of island (or quasi-island) in the head of the island sea power, had a considerable impact upon the Athenians citizens' consciousness. Many a decision was made by them on the basis of this idea during the Peloponnesian war. Only after the defeat of Athens (and therefore, after its weakening) did this approach begin to be revised.