The movements of the Russian Army were at first partly successful. Under the Grand Duke Nicholas it invaded East Prussia, invested the fortress of Königsberg, and reached the Masurian Lake region. The Southern Russian Army entered the north of Austria, cleared Galicia as far as the River San, and invested Przemysl. Its advance was, however, checked by the severe defeat which it suffered at Tannenberg, and it was forced to retire from East Prussia, which it again invaded in October. In the meantime, the Germans assembled a large army in Silesia, and advancing from Posen, forced the Russians to retire into Poland. Soon afterwards the Germans invaded Russia itself, and gained a victory at Grodno. In Austria the Russians were more successful, and after defeating the Austrian Army at Rawazuska, succeeded in capturing the stronghold of Przemysl which had been considered impregnable. On March 18 an unsuccessful attempt was made by the combined British and French Fleets to force the Dardanelles. This was the beginning of the Gallipoli campaign. In German South-West Africa General Botha landed at Swakopmund, near Walfish Bay, in February, and advanced to Jackalswater and Riet. A British Expeditionary Force also began operations in the Cameroons, and there was some fighting in German East Africa. Naval warfare was practically at an end by the beginning of 1915, as all the German ships had been cleared off the high seas. The German Fleet itself had taken refuge in Kiel Harbour, and there was nothing for the British Fleet to do but to wait patiently, in the hope that it would one day emerge and give battle. During March the blockade of Germany began, but the problem of how to deal with neutrals had not been solved, and the Germans were able to get all they wanted through Holland and the three Scandinavian countries. The 1st Battalion [Sidenote: 1st Batt. Nov. 1914.] On the 14th the 20th Brigade marched through Bailleul, Steenwerck, Sailly, Bac-St.-Maur to the trenches in the neighbourhood of Fleurbaix, where it relieved the 19th Brigade. The Grenadiers were on the right, the Scots Guards in the centre, and the Border Regiment on the left. Brigadier-General F. J. Heyworth, D.S.O., arrived from England, to take over the command of the Brigade. Throughout November the Brigade remained in the same line of trenches. At first there was a great deal of rain, but towards the end of the month it changed to snow and was bitterly cold. The men suffered very much from trench feet, as the ground was in a shocking condition. Goats' skins were issued, and also some white smocks for patrol duty at night, as the dark uniforms showed up so clearly in the snow.