Marshal Kutuzov reached Vilna on December 12th to control the hitherto independent movements of Chichagov and Wittgenstein. His own troops were following under Tormazov, but they were so shattered by the long march from Moscow that their offensive power was for the time at an end, and they were cantoned about Vilna. Chichagov was to follow to the Niemen to support Platov and the advance-guards which hung on the heels of the retreating French. Wittgenstein was ordered to intercept Macdonald on his expected retreat to the Niemen, while Paulucci was to press him in rear. Sacken’s army, supported by the Mozyr force, now under Tuchkov II, and a detachment from Bobruisk, was to deal with Schwarzenberg. The Emperor Alexander reached Vilna on December 22nd, and at once devoted himself to the task of endeavouring to save the lives of his captured enemies. The hospitals were choked with the Russian sick, and the French prisoners, almost all ill and helpless, were perishing wholesale. Biscuit and bread they received, but there was no other help for them. Gangrened wounds, frost-bite, and typhus produced by filth, hunger, and putrefaction, swept them away. In three weeks 15,000 are said to have died. Alexander and Constantine made magnificent efforts to cope with the awful mass of human misery. Reckless of personal danger, they personally superintended the relief operations; the Grand Duke nearly died of the fever which he caught in the midst of his labour of humanity. St. Priest was transferred from the work of collecting the Russian stragglers to that of superintending the hospitals of the prisoners, for which his French origin especially fitted him. Macdonald, before Riga, received his orders to retreat on December 18th, and started next day in two main columns, he himself leading the way with Grandjean’s division, a Prussian infantry brigade, and Massenbach’s cavalry; while Yorck followed a day’s march behind the rest of the Prussians. Wittgenstein himself could hardly intercept him; but the flying detachments of Kutuzov II and Diebich, thrown far forward, might hope to impede Macdonald’s march. The Marshal on reaching Koltiniani divided his own column, taking advantage of two roads thence to Tilsit, and intending to reunite his whole corps at Tauroggen. Kutuzov II was too weak to intercept him; but Diebich, with his 1500 cavalry and a few sledge-guns, got between Macdonald and Yorck on the 25th, and boldly proposed to the latter a conference in order to prevent useless bloodshed. After some hesitation Yorck at last made up his mind, and on the 30th concluded the famous convention of Tauroggen, by which the Prussians were declared neutral. The results were incalculably important, but belong rather to the history of the German War of Liberation. The immediate consequence was that the wreck of the _Grande Armée_ was weakened by 16,000 or 17,000 excellent soldiers and 60 guns.