Former colleagues and Coloradans who knew former U.S. Sen. Mike Enzi mourned the death Monday of the 77-year-old former shoe salesman from Gillette, Wyoming, who retired earlier this year after serving four terms in the Senate.

Enzi died surrounded by family and friends at UCHealth Medical Center of the Rockies in Loveland, three days after he was airlifted there with a broken neck following a bicycle accident near Gillette, a former spokesman for the Republican told the Associated Press.

A political career that spanned nearly five decades began when Enzi was elected to two four-year terms as mayor of Gillette before winning election to the Wyoming legislature in the mid-1980s. He was elected in 1996 to the U.S. Senate seat previously held by Republican Alan Simpson and won re-election three times before declining to seek a fifth term last year.

Condolences poured in Tuesday on social media.

“Senator Enzi was a great friend, a dedicated public servant, and a man of integrity,” tweeted U.S. Rep .Ken Buck, a Windsor Republican. “Praying for his wife Diana, the Enzi family, and all those devastated by his sudden passing.”

Tweeted former U.S. Sen. Cory Gardner, a Colorado Republican: “Sen. Mike Enzi was a kind and gentle person with a heart of faith and service. Jaime and I share in grief and our heartfelt sympathy goes to Diana and the Enzi family. Mike led us in prayer and will continue to lead us from above.”

“Mike Enzi was a neighbor, filled with kindness, who always looked for bipartisan agreement,” tweeted U.S. Sen. Michael Bennet, a Colorado Democrat. “My thoughts are with his family and loved ones.”

Michael Fields, executive director of conservative advocacy organization Colorado Rising Action, tweeted a photo of himself standing with Enzi.

“I’ll never forget my time interning for Senator Enzi,” Fields wrote. “He was not only a great senator, but also a great person. My prayers are with the Enzi family.”

Joe Jackson, executive director of the Colorado Republican Party and a former Capital Hill aide for a member of the Wyoming delegation, told Colorado Politics he had the honor of meeting Enzi on many occasions.

“He was a thoughtful, caring and kind man who was always interested in how a low-level staffer was doing,” Jackson said in a text message. “He truly was someone that everyone involved in politics – in either party – should look up to as how to make a difference, and do it in a civil way. My prayers are with his family and friends.”

Jonathan Finer, chief of staff for the Colorado House GOP, recalled on Facebook what he described as his fondest interaction with Enzi, who chaired the Senate Budget Committee, when Finer was an intern with the committee in 2015.

Enzi, it seems, hadn’t realized committee staff would be occupying his Capitol hideaway office to be near the Senate floor during a marathon session voting on budget amendments.

“While we were working, in strolls the Senator with his briefcase, newspaper and a big ol’ donut with pink frosting and sprinkles that would make Homer Simpson proud. He just said, ‘Oh, sorry to b other y’all, I’ll let you get back to it!'”

Finer wrote that the senator’s “immediate and gracious response to us using HIS office has stuck with me and, from my perspective, perfectly encapsulated his kind demeanor.”

Added Finer: “Rest In Peace, Senator.”

– The Associated Press contributed to this story.