No light task remained for the shattered Italian armies, for the Austrians had been greatly reinvigorated by their success, and continual reinforcements were arriving from the Russian front. Italy had never been a match unaided for her hereditary foes, and the prospect of British and French assistance was needed to stem the torrent of invasion descending from the mountains. The Italians fought well, and politically the nation pulled itself together; but one by one the Austrians captured in November the heights between the Piave and the Brenta which protected the Venetian plain, and it was not until 4 December that the French and British were able to relieve the pressure by taking up their respective quarters on the two cardinal positions of M. Grappa and the Montello. Even so the Austrian advance continued, while a bridgehead was secured across the Piave at Zenson. After a four days' battle on 11-15 December the Austrians reached the limits of their invasion at M. Asolone and M. Tomba on the east, and M. Melago on the west, of the Brenta valley; and before the end of the year the Italians were recovering slopes on M. Asolone and the French those of M. Tomba, while the bridgehead at Zenson was destroyed. Fighting went on well into 1918 without much material change in the situation until Austria was called upon to take her part in the final enemy onslaught in June. Nevertheless the Central Empires had achieved the most brilliant of their strategical triumphs. At slight cost to themselves they had bitten deep into Italian territory, taken a quarter of a million prisoners, 1800 guns, and vast quantities of munitions and stores, and had imposed a greatly increased strain upon the Allies who alone stood between them and victory on that Western front which Ludendorff had selected for the final test of war. CHAPTER XVII THE EVE OF THE FINAL STRUGGLE