Former Michigan congressman John Conyers, the longest-serving African-American member of Congress, passed away on Sunday, a family spokesperson confirmed. He was 90.

A fierce champion for civil rights, Conyers served in Congress for 53 years and became a powerful force in his caucus. He served as chairman of the House Judiciary Committee and helped found the Congressional Black Caucus.

In 1964, Conyers became one of only six black House members when he was elected to the House by just 108 votes. Conyers led the charge for the creation of a federal holiday in honor of Martin Luther King Jr., four days after King was assassinated in 1968.

Conyers, known for being one of the most liberal members of Congress, was a vocal critic of the Vietnam and Iraq Wars.

Conyers resigned from Congress in 2017 after two women accused him of making unwanted sexual advances. Conyers denied the allegations.

He is survived by his wife, Monica Conyers, and his sons John III and Carl.