U.S. Rep. Elijah Cummings of Baltimore, a committee chairman known for his devotion to Baltimore and civil rights and for blunt and passionate speechmaking, died of longstanding health problems early Thursday morning, his office said. He was 68 years old.

The Democrat, a key figure in the impeachment inquiry into President Donald Trump as chairman of the House Oversight and Reform Committee, died at Gilchrist Hospice Care, a Johns Hopkins affiliate, at approximately 2:45 A.M., a spokeswoman said.

Cummings, who had been absent from Capitol Hill in recent weeks while under medical attention, had health issues in recent years. In 2017, he underwent an aortic valve replacement. The procedure, which aides described as minimally invasive in Cummings’ case, is used to correct narrowing of the aortic valve in the heart. The surgery led to an infection that kept him in the hospital longer than expected. He was later hospitalized for a knee infection, but he said this summer that his health was fine.

Cummings had not participated in a roll call vote since Sept. 11. His office said recently that he had undergone a medical procedure but the seriousness of his condition had not been known.

The committee he chaired, Oversight and Reform, is among three panels leading the impeachment inquiry of Trump, a Republican.

Sen. Ben Cardin, a Democrat who is the senior member of Maryland’s congressional delegation, said Cummings’ loss “leaves an irreplaceable void in our hearts, in our Maryland and in our Congress. Quite possibly no elected official mattered so much to his constituents.”

“I feel as though I lost a member of my family,” said former Baltimore Mayor Kurt L. Schmoke. “We were that close. He cared about people and making life better for others.”

Former Maryland Gov. Martin O’Malley said Cummings “believed that children were the messengers to a future we’ll never see, and it is our responsibility to give our kids a better life.”

Cummings was an active member of New Psalmist Baptist Church and was married to Maya Rockeymoore Cummings, who was elected chair of the Maryland Democratic Party in December 2018.

“It’s been an honor to walk by his side on this incredible journey,” his wife said in a statement. “I loved him deeply and will miss him dearly.”