But the engagement of the allies appears to have had other objects also, larger than that of protecting Platæa, or establishing commemorative ceremonies. The defensive league against the Persians was again sworn to by all of them, and rendered permanent: an aggregate force of ten thousand hoplites, one thousand cavalry, and one hundred triremes, for the purpose of carrying on the war, was agreed to and promised, the contingent of each ally being specified: moreover, the town of Platæa was fixed on as the annual place of meeting, where deputies from all of them were annually to assemble.[390] This resolution is said to have been adopted on the proposition of Aristeidês, whose motives it is not difficult to trace. Though the Persian army had sustained a signal defeat, no one knew how soon it might reassemble, or be reinforced; indeed, even later, after the battle of Mykalê had become known, a fresh invasion of the Persians was still regarded as not improbable,[391] nor did any one then anticipate that extraordinary fortune and activity whereby the Athenians afterwards organized an alliance such as to throw Persia on the defensive. Moreover, the northern half of Greece was still _medizing_, either in reality or in appearance, and new efforts on the part of Xerxes might probably keep up his ascendency in those parts. Now assuming the war to be renewed, Aristeidês and the Athenians had the strongest interest in providing a line of defence which should cover Attica as well as Peloponnesus, and in preventing the Peloponnesians from confining themselves to their isthmus, as they had done before. To take advantage for this purpose of the new-born reverence and gratitude which now bound the Lacedæmonians to Platæa, was an idea eminently suitable to the moment, though the unforeseen subsequent start of Athens, combined with other events, prevented both the extensive alliance and the inviolability of Platæa, projected by Aristeidês, from taking effect.[392] [390] Plutarch, Aristeidês, c. 21. [391] Thucyd. i, 90.