navy, the German government ordered general mobilisation and declared war on Russia. Hostilities commenced on the Polish frontier, the French government ordered general mobilisation and next day the German government sent an ultimatum to Belgium, demanding passage through Belgian territory, as German troops crossed the frontier of Luxembourg. Military operations began on the French frontier, Libau was bombarded by a German light cruiser and the British government guaranteed naval protection for French coasts. On 3 August the Belgian Government refused German demands and the British Government guaranteed military support to Belgium, should Germany invade. Germany declared war on France, the British government ordered general mobilisation and Italy declared neutrality. On 4 August the British government sent an ultimatum to Germany and declared war on Germany at midnight on Central European Time. Belgium severed diplomatic relations with Germany and Germany declared war on Belgium. German troops crossed the Belgian frontier and attacked Liège. Tactical developments Liège forts Liège is situated at the confluence of the Meuse which, at the city, flows through a deep ravine and the Ourthe River, between the Ardennes to the south and Maastricht (in the Netherlands) and Flanders to the north and west. The city lies on the main rail lines from Germany to Brussels and Paris, which Schlieffen and Moltke planned to use in an invasion of France. Much industrial development had taken place in Liège and the vicinity, which presented a considerable obstacle to an invading force. The main defences were a ring of twelve forts from the city, built in 1892 by Henri Alexis Brialmont, the leading fortress engineer of the nineteenth century. The forts were sited about apart to be mutually supporting but had been designed for frontal, rather than all-round defence. The forts were five large triangular (Barchon, Fléron, Boncelles, Loncin and Pontisse), four small triangular (Evegnée, Hollogne, Lantin and Liers) and two small square forts (Chaudfontaine and Embourg). The forts were built of concrete, with a surrounding ditch and barbed-wire entanglements; the superstructures were buried and only mounds of concrete or masonry and soil were visible. The large forts had two armoured turrets with two guns each, one turret with two guns and two cupolas with a howitzer each. Four retractable turrets contained a quick-firer each, two before the citadel and two at the base. A retractable searchlight was built behind the turret with a range of . Small forts had