On 20th Oct. Mackensen attacked on the whole line in the Dobrudja, and five days later he was on the vital Cernavoda Bridge. Constanza, the Roumanian Black Sea port, had fallen, and so far from ever being in a position to take Turkey or Bulgaria in the flank, the Roumanians were now themselves on the verge of being outflanked on the Danube. Meanwhile, on the other arm of the nut-crackers, von Falkenhayn, despite trifling set-backs, was pressing on. The Törzburg Pass (21st Oct.), Predeal Pass (23rd Oct.), Vulkan Pass (25th Oct.), Roter Turm Pass (31st Oct.) were all scenes of Roumanian reverses, and by 15th Nov. the bulletins were bringing the daily news that the Roumanian retreat continued. On 23rd Nov. Falkenhayn was advancing on Bucharest; Mackensen had crossed the Danube at Islatz and Simnitza; and farther west Orsova and Turnu-Severin had fallen. All the German composite forces could now be deployed in Roumania, and the end followed swiftly. Mackensen and Falkenhayn were in touch on 26th Nov.; Campolung was captured 29th Nov.; Bucharest, Ploeshti, and Sinaia fell on 6th Dec.; and with them went the Roumanian oil-fields, the wells of which had, however, been very thoroughly damaged by Captain Norton Griffiths and a small British party in order to prevent their use by the Germans. (They were restored in some eight months.)
On 8th Dec. the Germans estimated their Roumanian captures as 70,000 men and 184
guns; and it is true that only a portion, though a considerable one, of the Roumanian armies was able to effect a retreat with the Russians to the line of the Sereth defences. Fighting went on till the end of the year, and was continued into 1917 until the Roumanians were forced to sign the Treaty of Bucharest—revoked by the Allies at the end of the war.
Roumania's fate, following the tragedy of Serbia and the Allies' withdrawal from Gallipoli, strengthened the Greek military party round King Constantine, which was now openly pro-German. Against these influences M. Venizelos proved powerless, though Greek volunteers were at the same time joining the Venizelos party, and ready to fight with the Allies. This division of opinion in Greece was illustrated in the middle of August (1916), when two divisions of the 4th Greek Army Corps surrendered to the Bulgarians, who had advanced to the Greek port of Kavalla, while the 3rd Division of the same corps joined the Allies at Salonika. The pro-Germans had carried all before them at the last Greek elections (Dec., 1915), when the Venizelists declined to poll; and the danger of finding themselves suddenly attacked in the rear discouraged an Allied offensive against the Bulgarians until the autumn of 1916, when the newly equipped Serbian army arrived from Corfu, ready and eager to fight its way home, joining the force under General Sarrail, which already included Russian, Italian, and Portuguese contingents, besides French and British. Following pro-German riots against the Allied embassies in Athens, too, a 'pacific blockade' of the Greek coast had been enforced, and a firm Note presented to the Greek Government demanding the demobilization of the Greek army and a new general election, to be freely conducted. When these demands had been accepted and a new Government formed—though the king's pro-German sympathies remained as marked as ever—General Sarrail resumed, in September, the offensive against the Bulgarians. The main advance was undertaken by the French and Serbian divisions, with a Russian contingent, in the direction of Monastir, General Milne's British column meantime pushing the Bulgarians back from the Struma line. Two months' fighting saw the Serbians, who had borne the brunt of the attack at this point, marching back into Monastir in triumph, having turned the Bulgar-German forces out of it on 18th-19th Nov. The British, at the same time, kept the enemy busy at the other end of the line, occupying a number of villages, and pushing the Bulgarians back beyond the railway between Seres and Demir-Hissar. With their heavy commitments elsewhere the Allies were for the time being unwilling to extend their military operations beyond Monastir.
Italian Campaign, 1916
Italy, who for political as well as military reasons had declined further assistance in the Balkans, had her share of hard fighting within her own frontiers in 1916. Before she could resume her advance on Gorizia and Trieste (held up in the early winter of 1915) the Austrians attacked in turn from the Trentino under General Conrad von Hoetzendorff, who, planning a drive on the Mackensen scale, aimed a blow at the tempting Venetian plains. The grand attack, supported by upwards of 2000 heavy guns on a 30-mile front between Val Sugana and Val Lagarina, and delivered on 14th May by some 350,000 first-class troops, smashed a way through in the centre. Though the flanks held firmly, and the Italians, roused to fury by the invasion, fought magnificently among the mountain heights, General Cadorna ordered the line to be withdrawn from its untenable positions until it was south of Asiago. Pressing their advantage with every means at their disposal, the Austrians announced in an Army Order on 1st June that only one mountain intervened between their troops and the Venetian plains. Cadorna, however, had now been reinforced, and two days later was able to reply that the Austrian offensive had been checked. For the rest of the month he was content, in this sector, to sustain the continued but unavailing assaults of the enemy, while he prepared his own great counter-attack on the Isonzo front, with Gorizia, the gateway to the plateau of the Carso which led to Trieste, as his immediate objective. This dramatic move, heralded by an intense bombardment on 6th Aug., was entrusted to the Duke of Aosta, whose Third Army, after three days' fighting of the fiercest description, carried the last heights defending the town and entered Gorizia in triumph. Following the retreating enemy across the Carso, the Italians, whose enthusiasm for the war had been greatly stimulated by this fine feat of arms—Italy's belated declaration of war on Germany followed upon the Gorizia victory—continued their advance across the northern end of that formidable plateau, winning a number of considerable battles, and capturing before the end of the year between 30,000 and 40,000 prisoners, but never succeeding in mastering the Carso as a whole.
Naval War in 1916—Battle of Jutland
The battle of Jutland, which took place on 31st May, 1916, overshadows all other naval operations in that year; nevertheless, there were several other events of importance which preceded it, or were in some way related to its occurrence afterwards. For example, in the
earlier months of the year the German raider Moewe was at large, and inflicted considerable damage on British shipping before returning safely to a German port; the mercantile submarine Deutschland left Germany for the United States and returned in safety; and another German submarine, U 53, also crossed the Atlantic with more belligerent intent, and sank several merchant vessels off Rhode Island on 8th Oct. The new development of the submarine war, in which Germany declared her intention of sinking merchant ships at sight, began on 1st March, and one of its most important consequences was the dispatch of a United States Note by President Wilson to Germany (18th April) in respect of the sinking without warning of the Sussex and other unarmed vessels. Another outcome of the German submarine warfare was the sinking of British hospital ships in the Mediterranean. Furthermore, following the battle of Jutland, and related in some respects to its only partially decisive character, the Hampshire, with Lord Kitchener and his Staff on board, was sunk off the north of Scotland (5th June) by striking a mine that is said by the Germans to have been laid by one of their submarines; and on 19th Aug. the German High Seas Fleet was able to come out again, though it sought no action, but avoided one. Two British light cruisers, the Nottingham and Falmouth, were sunk in the search for its whereabouts.
The 'partially decisive', or 'indecisive', character of the battle of Jutland are relative terms, and their exact implication has been, and must continue to be for a long time, a matter of controversy. On the one hand, the aim of Admiral von Scheer, the Commander-in-Chief of the German High Seas Fleet—to catch a portion of the British Grand Fleet and attack it while isolated and unsupported—was frustrated, and in that respect the German admiral failed. On the other hand, Admiral Sir John Jellicoe's purpose of destroying the German Fleet, if and when he succeeded in engaging it, also failed, as may be understood from its subsequent emergence from its harbour in August, and the later development of the German submarine campaign, which could not have taken place had not the Germans possessed the framework of a fleet to support the under-water vessels. Sir John Jellicoe justifiably claimed that his action preserved intact the main forces of the British Grand Fleet, and left them as before in command of the outer seas, while demonstrating to the Germans that they could not again engage in a naval battle on a large scale with any hope of success. Admiral von Scheer was entitled to claim that he had engaged a superior British force, had inflicted on it more material damage than he had sustained, and had withdrawn the bulk of his forces to remain, as before, a menace, not to British safety, but to British unfettered control of the seas. The details, in outline, of the battle of Jutland are as follows.