This attempted break-through (July 1-12) soon changed into a battle of attrition (July 14, 1916, to March, 1917). The Allies' plan now was gradually to shatter the German resistance by a continuous push along the whole line, and by vigorous action at the various strong-points. The gains of ground diminished, but the German reserves were gradually used up. In spite of their hastily constructed system of new defences, the Germans realised the precarious nature of their new lines, and were forced, in March, 1917, to fall back and shorten their front. [Illustration: THE PHASES OF THE BATTLE OF ATTRITION. NORTH OF THE SOMME. _The Franco-British troops enlarge the conquered positions and attack the centres of resistance: Combles and Thiepval (July 14--September 1)._] [Illustration: _Combles and Thiepval turned and conquered, after being surrounded (September--November)._] [Illustration: _The Allies advance toward their main objectives: Bapaume and Péronne (November--March)._] [Illustration: SOUTH OF THE SOMME. _The 6th Army (French) held by the Somme Marshes, took up its new position. The 10th Army (French) assembled on its right (August--September)._] [Illustration: _The 10th Army attacked, but was held in front of Chaulnes (September--October)._] [Illustration: _The 10th Army (French) failed to encircle Chaulnes, and consolidated its new positions (October--November)._] [Illustration: FIELD-MARSHAL HAIG.] THE ATTEMPTED BREAK-THROUGH. The British Attack On July 1, the front of attack, about 21 miles long, extended from Gommécourt to Maricourt. The attack was made by the 4th Army (Gen. Rawlinson), comprising five army corps, and by three divisions of the right wing of the 3rd Army (Gen. Allenby). The main sector of attack, lying between the Ancre and Maricourt, forms a 90° salient; the summit of which encircled Fricourt. The first German positions included Ovillers, La Boisselle, Fricourt, Mametz and Montauban, and formed the objective of the attack. The latter, directed generally towards Bapaume, was delivered against both flanks of the salient. From the start, the attack was held before the western side of the salient, in spite of the great heroism of the British. The right wing, on the southern side, succeeded in carrying the first German position. [Illustration: _Photo, Russell, London._ GENERAL RAWLINSON.] [Illustration: _Photo, F. A. Swaine, London._ GENERAL ALLENBY.] In face of this result, Field-Marshal Haig decided to push home the attack on his right (three corps under Gen. Rawlinson), while his left (two corps under Gen. Gough) would continue to press the enemy, and thus form the pivot of the manœuvre. [Illustration: THE DOTTED ZONES ON THIS AND THE FOLLOWING SKETCH-MAPS REPRESENT THE GERMAN LINES OF RESISTANCE.]