Between 1809 and 1811, Napoleon's empire stood at its greatest extent. In 1809, Napoleon turned 40, and became concerned at his lack of an heir. Hoping that a younger woman would conceive more readily, he had his marriage to Josephine annulled and started looking for a suitably aristocratic second wife. Alexander I turned Napoleon's inquiries about his sister down, and Metternich stepped into the breach, offering Archduchess Marie Louise of Austria as a wife. In 1811, the new empress gave birth to a son, Napoleon II, known as the "King of Rome".
By 1810 to 1811, Napoleon's empire included nearly all of Europe except for the Balkans. It was comprised of an enlarged France (which had swallowed Belgium and Holland, parts of Germany, and the Italian coast all the way to Rome) and various puppet nations actually ruled by Napoleon or by a Bonaparte subservient to Napoleon. In addition to those lands he ruled over directly, Napoleon held alliances with Austria, Russia, Denmark, Sweden, and a greatly reduced Prussia. Essentially all of Europe was now "at war" with Britain, their resources and industry and populations being used to serve the French Empire. All of these states, from the Empire to the Napoleonic allies, participated in the Continental System.
Napoleon made good use of his large family, appointing his brothers and sisters as royalty throughout Europe. When he ran out of family, he switched to more distant relatives and the servants he believed most faithful. For instance, when Napoleon had to transfer his brother Joseph from Naples to rule over Spain, he made one of his leading generals, Murat, into the King of Naples. He also made his stepson, Josephine's son, into the viceroy of the Kingdom of Italy.
Napoleon's takeovers all followed a similar script. First, his army would take a region over. Then, Napoleon would impose his powerful influence on a collaborationist government made up of locals friendly to France as they drafted a new constitution. Napoleon then might impose his direct ruler, or the rule of a family member, or leave the collaborationist government in place so long as it remained loyal to him. From this position of power, Napoleon would encourage numerous reforms, spreading the ideals of the revolution throughout Europe.
Josephine, who had given birth to two children by her first husband, protested the annulment, suggesting that the lack of an heir was Napoleon's fault. Of course, Josephine was 46 by 1810, and contrary to the public image of timeless love, both engaged in numerous affairs. Marie Louise, Napoleon's new empress, was 18 when they married, and quickly produced the desired heir. Napoleon's decision to call this son the "King of Rome" greatly upset Pope Pius VII, though the Pope stopped protesting after Napoleon had him brought to France to remain under French custody. Oddly, Napoleon's marriage to Marie Louise, a Hapsburg, made him the nephew-in-law of Louis XVI, the king executed during the French Revolution.
With Napoleon now related to the king the Revolution overthrew, it seemed that France was moving full circle. This appearance was not merely symbolic: seeking loyal allies in France, Napoleon started making people who served him well into nobles. Within two decades of the French Revolution directed against aristocracy, a new aristocracy was coming into existence.