This monarch diminished the power of Thomas Pelham-Holles in favor of his trusted adviser, the Earl of Blute. During this monarch's reign, Prime Minister Spenser Perceval was assassinated and England agreed to the Peace of Amiens. This husband of Queen Charlotte defeated an attempt to reform the (*) East India Company, which aided the rise of William Pitt, the Younger. His rule saw the passage of the Stamp Act, and this British king's later life was marked by fits of madness, attributable, by some, to porphyria. For 10 
This monarch diminished the power of Thomas Pelham-Holles in favor of his trusted adviser, the Earl of Blute. During this monarch's reign, Prime Minister Spenser Perceval was assassinated and England agreed to the Peace of Amiens. This husband of Queen Charlotte defeated an attempt to reform the (*) East India Company, which aided the rise of William Pitt, the Younger. His rule saw the passage of the Stamp Act, and this British king's later life was marked by fits of madness, attributable, by some, to porphyria. For 10 points, name this British king who lost the American colonies and saw his rule end in the regency of his son, George IV.
This monarch diminished the power of Thomas Pelham-Holles in favor of his trusted adviser, the Earl of Blute.
{George III} [prompt on {George}]