"It is entirely possible that the first few defeats of the Russian campaign were in fact what ultimately saved the French Empire.
It has been put forward by many historians that the Tsar had expressed his intentions to have his entire capital burnt to the ground if it were to fall into the hands of the Grande Armée. Therefore, one may argue that Napoleon’s defeat at Smolensk in 1812 and subsequent retreat to the Duchy of Warsaw to lick his wounds was the only thing that saved the French from starvation in the frost of winter. Nevertheless, it was rightfully applauded as a great Russian victory, and the friendship between the Tsar and the Emperor was irremediably damaged.
The soldiers of the Grande Armée, however, had little time to rest and recuperate, for the Government of King George had been mustering a new Coalition with the Spaniards, the Portuguese, as well as the Russians and the Austrians, who had taken up arms against Napoleon despite his marriage with Marie-Louise, the daughter of Emperor Francis I.
Napoleon’s greatest victory during the so-called German Campaign of 1813 happened near the city of Wolfsburg, and made the French victory in Saxony an inevitability. It also cemented France’s power over most of the Confederation of the Rhine. Although a nationalist sentiment emerged, it never took roots and was eventually of no avail.
Immediately following the French victory in Germany, the Duke of Wellington, who had performed well throughout his own Peninsular Campaign, deemed it wiser to remain west of the Pyrenees, for even had he reached Paris, he most certainly would not have been able to hold the French capital. Indeed, Napoleon was positively enraged at the turn of events, and as Charles XIV John of Sweden, who had been in league with the Tsar, pledged a renewed allegiance to the French Empire, he turned his attention toward Spain, although he did so warily.
It took the Grande Armée a little more than three months to bring the Invasion of Spain to its successful conclusion, as the British were mainly concerned with enacting an orderly retreat: a decision had been made by the Earl of Liverpool to stop intervening in continental affairs and prioritize the business of the colonies and expand the influence of the British Empire in the Caribbean and Africa.
Therefore, Napoleon was to dominate all of Europe, and although his Empire became quite vast, it could not rival the might of the Royal Navy. His reign lasted until 1823 when he died of a peptic ulcer that had degenerated into gastric cancer. And it was then Napoleon Francis Charles Joseph Bonaparte who took the reins of power. However, he was a poor monarch in the first decade of his reign. It was only during a short campaign against the rebellious King of Sweden that the company of his marshals, away from his overbearing mother, revealed his knack for command and tactics, and his passion for soldiering. His strength of character was exacerbated by the passing of his grandfather, Francis I, Emperor of Austria, in 1835. Nevertheless, it was his uncle, Ferdinand I, who succeeded Francis, and Napoleon II had to wait until the Revolutions of 1848 for his feeble-minded uncle to abdicate the throne to him thanks to clever political manoeuvring on the part of the ever-scheming Talleyrand.
It was also after Francis I’s death that Napoleon II took Princess Louise of Prussia as a wife; a marriage that was as strategically sound as it was loveless. With the help of Prince Eugene of Beauharnais, who was a consummate diplomat and tactician, the Emperor managed to place his numerous progeny on nearly every major European throne.
Ultimately, the reign of “the Eaglet” was long and prosperous, and punctuated with successful military campaigns, despite he and his descendants having inherited an Empire teeming with tensions and even unrest, which made it difficult to concentrate on the development of a navy and a network of colonies that could measure up to those of George IV, and then William IV. Such a tremendous task was to be undertaken only after his death in 1868, by his son Philippe Napoleon Eugene Bonaparte, who ascended the throne as Napoleon III. It was then continued under Louis Charles Auguste Napoleon Bonaparte, who became known as Charles I. The latter had no inclination for war, and was rather more interested in architecture and the arts. Therefore, he had been keen on putting together a competent general staff and a formidable admiralty to care for the military aspect of his reign, which proved critical to the French Empire during the Northern War and the Caucasian War. Throughout the decades, there were a handful of revolutions and demands for a modicum of independence, which were mostly granted when it was not in any way harmful to the resources of the Empire.
Charles I’s son, Victor Hubert Napoleon Bonaparte Emperor, succeeded his uncle as Victor I merely three years ago, in 1921, and has had to deal with a rather difficult situation in the Pacific, where the imperialistic ambitions of the “heavenly sovereign” of Japan. There is no telling, however, if such an inexperienced statesman shall be able to maintain what is left of the overseas French Empire, even with an already well-oiled bureaucracy with numerous satellite states."
François Victor Alphonse Aulard, preface to the last chapter of Modern France, A Political History.