So bitter however was the opposition made by Thucydides and his party to this projected expenditure—so violent and pointed did the scission of aristocrats and democrats become—that the dispute came after no long time to that ultimate appeal which the Athenian constitution provided for the case of two opposite and nearly equal party-leaders—a vote of ostracism. Of the particular details which preceded this ostracism, we are not informed; but we see clearly that the general position was such as the ostracism was intended to meet. Probably the vote was proposed by the party of Thucydides, in order to procure the banishment of Pericles, the more powerful person of the two and the most likely to excite popular jealousy. The challenge was accepted by Pericles and his friends, and the result of the voting was such that an adequate legal majority condemned Thucydides to ostracism. And it seems that the majority must have been very decisive, for the party of Thucydides was completely broken by it: and we hear of no other single individual equally formidable, as a leader of opposition, throughout all the remaining life of Pericles.
The ostracism of Thucydides apparently took place about two years after the conclusion of the Thirty Years’ Truce (443-442 B.C.), and it is to the period immediately following, that the great Periclean works belong. The southern wall of the Acropolis had been built out of the spoils brought by Cimon from his Persian expeditions; but the third of the Long Walls connecting Athens with the harbour was the proposition of Pericles, at what precise time we do not know. The Long Walls originally completed (not long after the battle of Tanagra, as has already been stated) were two, one from Athens to Piræus, another from Athens to Phalerum: the space between them was broad, and if in the hands of an enemy, the communication with Piræus would be interrupted. Accordingly, Pericles now induced the people to construct a third or intermediate wall, running parallel with the first wall to Piræus, and within a short distance (seemingly near one furlong) from it: so that the communication between the city and the port was placed beyond all possible interruption, even assuming an enemy to have got within the Phaleric wall. It was seemingly about this time, too, that the splendid docks and arsenal in Piræus, alleged by Isocrates to have cost one thousand talents [£200,000 or $1,000,000] were constructed; while the town itself of Piræus was laid out anew with straight streets intersecting at right angles. Apparently this was something new in Greece—the towns generally, and Athens itself in particular, having been built without any symmetry, or width, or continuity of streets: and Hippodamus the Milesian, a man of considerable attainments in the physical philosophy of the age, derived much renown as the earliest town architect, for having laid out the Piræus on a regular plan. The market-place, or one of them at least, permanently bore his name—the Hippodamian agora. At a time when so many great architects were displaying their genius in the construction of temples, we are not surprised to hear that the structure of towns began to be regularised also. Moreover we are told that the new colonial town of Thurii, to which Hippodamus went as a settler, was also constructed in the same systematic form as to straight and wide streets.