Only a brief summary of the Battle of Tannenberg can be given here; reference has been made to Liddell-Hart's 'History of the First World War', Barbara Tuchmann's 'August 1914, Hoffman's 'The War of Lost Opportunities', S.L.A.M. Marshall's 'World War I' , Parkinson's "Tormented warrior- Ludendorff and the Supreme Command" and Stone's 'The Eastern Front, 1914 - 1917'. The provisions of the Franco-Russian agreement required an attack by Russia of 800,000 men within 15 days of mobilisation (Liddell Hart, paper-back edition, page 97) but the Russian armed forces, rapidly mobilised, were illtrained and short of provisions and ammunition. Despite these inadequacies two Russian armies, the 1st and the 2nd, were ordered to attack East Prussia by the middle of August 1914. Because of the north-south barrier formed by the Masurian Lakes, any attempt to invade Prussia from Russia must force a separation between the two Armies of about 60 miles. Rennenkampf, in command of the 1st Army, was to attack to the north at Gumbinnen and threaten the fortified city of Konigsberg through the narrow Insterberg gap, while Samsonov's 2nd Army was required to attack the Prussian border over 60 miles to the south. The two Armies were to combine in a pincer movement, trapping the defending German forces between them. Before the war Russia had deliberately built her railways at a different gauge to the German railway gauge because of fear of German invasion and the Russian 2nd Army soldiers had therefore to travel by foot, over completely inadequate tracks in the heat of the summer. Samsonov was therefore delayed for four days behind Rennenkampf and his men, short of food and nearly starved, were exhausted by their ordeal, many arrived at their destination disabled and with their feet bound in rags. To complicate matters further, Rennenkampf and Samsonov detested each other. Their overall Commander, Jhilinsky, operating from an HQ situated over 100 miles to the East, had very little understanding of the actual events as they occurred and had very poor communications with his subordinates. However these deficiencies did not prevent him from issuing peremptory ill-advised commands to them. Initially Rennenkampf's success in his attack at Gumbinnen caused the German commander, von Prittwitz, to telephone Moltke that he was about to evacuate the area and retire to behind the Vistula River. Prittwitz later changed his mind and decided to stand, but he neglected to inform Moltke of this and was immediately superseded by the Hindenburg-Ludendorff combination, with Ludendorff in actual tactical command. Before he was dismissed Prittwitz, however, had ordered General von Francois' Corps to disengage and move south to attack the left of Samsonov's 2nd Army, making use of the Prussian internal railway facilities, On his arrival, Ludendorff agreed with these orders but took them further by ordering the other two northern Corps to march south-west and join up with the forces traveling by rail, leaving Rennenkampf’s 1st Army to be watched only by a thin German cavalry screen. Ludendorff took little risk in doing this because Jhilinsky, thinking that the two German Corps had retired upon Königsberg, had ordered Rennenkampf to prepare to attack Königsberg to the north west, even though this opened the gap between the two Russian Armies and Jhilinsky used radio and a simple code, easily broken by the Germans, to send these orders. Rennenkampf obeyed them, albeit very slowly as his men were exhausted and he considered that his forces were inadequate for the task. Samsonov, in the south, goaded by wireless messages sent in clear from Jhilinsky repeatedly ordering him to advance, thought that he was pursuing a retreating German Army. However Samsonov was misled because there was no actual retirement, just that the weak German centre had relocated to a better position. Samsonov therefore completely misread the situation and also ignored, or was not informed about, the new threat to his left. By then the components of his army had become separated and his front extended over 20 miles. Ludendorff was able to follow all these Russian intentions because of the insecure wireless messages and, realising that there would be a golden opportunity to envelop Samsonov's Army, he ordered von Francois to attack Samsonov's left wing. If von Francois had obeyed Ludendorff on that date, the 26th August, this attack could never have been effective as Samsonov had still not far advanced enough to the north to be ahead of von Francois. Fortunately for Ludendorff, von Francois’ guns were still on the train and he disobeyed his orders and insisted on delaying for a further day until the 27th August. This delay gave Samsonov time to advance further to the north. Samsonov's forward movement had thus placed him directly between the right and left German forces where he was vulnerable to a pincer attack from von Francois Corps, on his left and Mackensen's and von Below's Corps on his right. In fact Samsonov had pushed his army so far forward that von Francois was able to surround it on the 27th August - this was a direct result of von Francois' disobedience of the day before. On the afternoon of the 27th August the German trap closed and the Russian 2nd Army was destroyed; over 90,000 Russians were captured. Samsonov committed suicide when he realised the magnitude of his defeat. Despite radio calls for assistance, Rennenkampf did not move. Colonel Hoffman has speculated, in his book "The War of Lost Opportunities" on page 34, that the personal enmity between Rennenkampf and Samsonov could not be disproved as a factor causing Rennenkampf's inaction. However, other authors (Norman Stone in particular) have been more charitable and it is likely that it was Jhilinsky who prevented Samsonov's relief by interfering and insisting on Rennenkampf's attack continuing towards Königsberg. Jhilinsky was so far out of touch with events that he never even realised that he had lost his 2nd Army until the 2nd September! Hoffman, who took a major part in the planning for the battle generously stated that the disgraced Prittwitz was mainly responsible for the victory of Tannenberg. Be that as it may, the rest of the world credited Ludendorff with the victory and Ludendorff, despite bouts of self doubt, insecurity and fears that he had repeatedly made the wrong decisions, claimed the responsibility for victory when writing his memoirs. In truth it was not Ludendorff who won the Battle of Tannenberg. Germany won the Battle for many reasons; reasons such as German generals making fewer errors than the Russian generals; Germany having the inestimable advantage of good internal rail communications and Ludendorff being greatly assisted by his capacity to know the Russian intentions as a result of incredible Russian laxity in radio security. There was, however, another very important reason why the Germans won - this was because General von Francois was so bloody minded that he refused to obey Ludendorff's orders!