(1759-1806) the youngest man ever to become Prime Minister of Britain (at the age of 24). He was Prime Minister from 1783 to 1801 and again from 1804 to 1806. His achievements included removing much of the corruption from British politics and improving the financial position of the country. He also introduced income tax and was responsible for the Act of Union (1800), by which Ireland became part of the United Kingdom. He is often referred to as Pitt the Younger and his father, the Earl of Chatham, as Pitt the Elder.