Indeed the Greeks were whole years gathering their forces, and when they did all meet at last, with their ships and men, Agamemnon, king of Mycenæ, Menelaus’ brother, took the lead of them all.  As they were sacrificing to Jupiter, a snake glided up a tree, where there was a sparrow’s nest, and ate up all the eight young ones, and then the mother bird.  On seeing this, Calchas foretold that the war would last nine years, and after the ninth Troy would be taken.