From the death of his father in 1820 until his own death in 1827, he was the heir presumptive to his elder brother, King George IV, both to the United Kingdom and the Kingdom of Hanover. Frederick was thrust into the British army at a very early age, appointed to high command at the age of 30, and commanded in a notoriously ineffectual campaign during the War of the First Coalition, which followed the French Revolution. Later, as Commander-in-Chief during the Napoleonic Wars, he reorganised the British army, putting in place vital administrative and structural reforms..