The 4th Earl Fitzwilliam, known as William Fitzwilliam, was a prominent British nobleman born in 1780. He inherited the title from his father in 1833 and was known for his significant contributions to the Whig Party and his involvement in various social reforms during the 19th century. Fitzwilliam was also a notable landowner, managing vast estates in Yorkshire and Ireland. He was an advocate for agricultural improvements and supported the development of local infrastructure, which helped boost the economy in his regions. He passed away in 1857, leaving a legacy of public service and philanthropy.