In 483 BC, a massive new seam of silver was found in the Athenian mines at Laurium. Themistocles proposed that the silver should be used to build a new fleet of 200 triremes, while Aristides suggested it should instead be distributed among the Athenian citizens. Themistocles avoided mentioning Persia, deeming that it was too distant a threat for the Athenians to act on, and instead focused their attention on Aegina. At the time, Athens was embroiled in a long-running war with the Aeginetans, and building a fleet would allow the Athenians to finally defeat them at sea. As a result, Themistocles's motion was carried easily, although only 100 warships of the trireme type were to be built. Aristides refused to countenance this; conversely Themistocles was not pleased that only 100 ships would be built. Tension between the two camps built over the winter, so that the ostracism of 482 BC became a direct contest between Themistocles and Aristides. In what has been characterized as the first referendum, Aristides was ostracised, and Themistocles's policies were endorsed. Indeed, becoming aware of the Persian preparations for the coming invasion, the Athenians voted for the construction of more ships than Themistocles had initially asked for. In the run up to the Persian invasion, Themistocles had thus become the foremost politician in Athens.