William M. Tweed, commonly known as Boss Tweed, was a powerful political figure in New York City during the mid-19th century. He was a leader of the Tammany Hall political machine, which was known for its influence over local politics and its ability to mobilize voters. Tweed's control over the city allowed him to amass significant wealth and power through corrupt practices. Tweed's reign came to an end in the early 1870s when his corrupt activities were exposed, leading to his arrest and conviction. He was charged with embezzlement and fraud, highlighting the rampant corruption in urban politics at the time. His downfall marked a significant moment in the fight against political corruption in the United States.