[186] _Embattled walls._ “Another essential basis of mechanical unity in the poem is the construction of the rampart. This takes place in the seventh book. The reason ascribed for the glaring improbability that the Greeks should have left their camp and fleet unfortified during nine years, in the midst of a hostile country, is a purely poetical one: ‘So long as Achilles fought, the terror of his name sufficed to keep every foe at a distance.’ The disasters consequent on his secession first led to the necessity of other means of protection. Accordingly, in the battles previous to the eighth book, no allusion occurs to a rampart; in all those which follow it forms a prominent feature. Here, then, in the anomaly as in the propriety of the Iliad, the destiny of Achilles, or rather this peculiar crisis of it, forms the pervading bond of connexion to the whole poem.”—Mure, vol. i., p. 257.