As the king left his daughter's apartments after a familial visit, madman Robert Damiens sprung from the dark with a pistol. Fired it at point-blank range, the bullet tore into the king's torso between his ribs, causing unstoppable bleeding that killed the king before midnight. The king's guard set upon Damiens and spared his life only to be found guilty of regicide (the first even attempted in France in 140 years) and drawn and quartered.
Almost instantly after the death of the king, the French changed their opinions and mourned the loss of someone great. Pompadour was taken out of the public light as Louis XVI was crowned and set to work to bring France triumphantly out of the unpopular war. The Duc de Richilieu managed a successful invasion of Hanover that summer, first overwhelming the Army of Observation and then defeating the English Duke of Cumberland's forces at the Battle of Hastenbeck and taking Hanover on August 11. On August 21, Richilieu begrudgingly agreed to Cumberland's armistice, though he felt he could invade further into the Germanies and challenge Prussia. The King of Denmark offered to broker peace, which France agreed to do, seeing that a long war would lose them their colonies and their only hope was seizing European bargaining chips at great cost. Britain made considerable demands, leaving France with only Quebec and Louisiana in North America and taking much of their holdings in Africa and India. Still, it was seen in Paris as a bad war for the time as Louis XVI needed to become settled.
Taking in support from the aristocracy of the Parliamente (to whom he granted civil authority in exchange for monetary advances, setting the stage for ending autocracy), Louis began reforming his army and, especially, his navy. The preempted war would eventually spark again, this time as Frederick II attempted an invasion of Sweden upon the death of Elizabeth of Russia in 1762 and the ascension of pro-Prussian Peter III. Russia planned conquest of Finland while Prussia hoped to push Sweden into something of a military vassal. England, Spain, and Austria joined with France against them, and the revitalized French army crushed Frederick's forces as Peter was overthrown by his wife Catherine (soon to be called "the Great"). France established significant international clout by the time of Louis XVI's death in 1765 due to tuberculosis, which also ravaged the court. Eleven-year-old Louis XVII came to the throne, advised by the Parliamente, which by reform gained a house of popularly elected representatives. Under him, France launched a new age of imperialism, establishing a sphere of influence in southeast Asia in Vietnam and Cambodia as well as numerous islands throughout the Pacific. War over Australia would drive the French and English against one another again in a long series of naval campaigns that would prove ultimately inconsequential other than producing maritime technology and significant monetary drain.
The nineteenth century would continue with moderate social reforms and on-again, off-again warfare between England and France. Balance maintained the European kings until the Industrial Revolution spawned an uprising of anarchists that would put an end to royalty in brutal fashion.
In reality, Robert Damiens attacked the king with a penknife. Though there were fears of poisoning, Louis XV survived, and Damiens was still found guilty of regicide. His was the last execution for regicide as the next round, in the French Revolution, would be supported by the people. After defeat by attrition in the Seven Years' War and a humiliating Treaty of Paris, France would back the American Colonies' rebellion against Britain, putting the government into further debt that would contribute to violent overthrow.