While the accession of new and formidable powers to the league was taking place, the energy of Napoleon seemed to rise with the difficulties against which he had to contend, and to acquire an almost supernatural degree of vigor. His shattered armies were reinforced, and, undiscouraged by the recollection of Moscow, he prepared again to make his power felt against the formidable odds which the energies of five empires were concentrating for his destruction. Already again in the month of April was he in the field, and in May occupied Dresden, driving his enemies before him. In August, however, the allies having been strongly reinforced, made their first attack upon that city. Through August and September there were constantly recurring battles, by which the French were so harassed that Napoleon at length resolved to retreat in the direction of Leipsic, and on the 15th of October his army, consisting of 175,000 men and 720 pieces of cannon, occupied that city, and encamped around it. The allies followed with 290,000 men and above 1300 guns. The 18th dawned, and the last hour of the French Empire began to toll. The celebrated battle of Leipsic was fought. The conflict of such masses was terrible, and was so disastrous to the French, that a retreat was resolved upon, which commenced the next morning, the allies entering the city as the French retired across the river. The battle of Leipsic was, perhaps, the most unfortunate in its results which Napoleon ever experienced; and the subsequent retreat of his army to the Rhine partook, in a measure, of the horrors of that from Moscow. While the discomfited French were retiring across the Rhine at Mayence, the allied troops followed closely on their footsteps, and Alexander entered Frankfort on the 5th of November. Napoleon had left on the 1st, remaining six days with his army on the opposite shores of the river, and reached Paris on the 9th. The day after, in the council of state, he unfolded the danger of his situation with manly sincerity, and with nervous eloquence referred to the invasion by Wellington of his southern frontiers, while the allies menaced the north. A levy by conscription was made of 600,000 men, and preparations to resist the invasion were immediately ordered. On the 1st of Dec. the allied sovereigns published a declaration from Frankfort, offering peace to France on condition that she would confine her limits between the Rhine, the Alps, and the Pyrenees. But the negotiation was protracted by Napoleon to gain time, until the impatient allies crossed the Rhine, and Denmark, Naples, and the Rhenish Confederation, joined the alliance. The allies had now accumulated forces so prodigious, for the invasion of France, that nothing in ancient or modern times had ever approached to their magnitude.