Frank Ryan, a three-time Pro Bowler who was the last quarterback to lead the Cleveland Browns to an NFL championship, died on Monday, his family said in a statement. He was 87.

Ryan had been battling Alzheimer’s disease and the family said chronic traumatic encephalopathy (CTE) "is suspected to have played a role in the progression of the disease." His brain was donated to Boston University’s CTE Center for study.

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"Our hearts are with the family and friends of Frank Ryan, as we honor the life of a Browns icon and championship-winning quarterback," the Browns said in a post on X.

Ryan was a standout quarterback at Rice University before he turned pro. The Los Angeles Rams selected him with the No. 55 overall pick in the fifth round of the 1958 draft. He played four years with the Rams before he joined the Browns.

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In Cleveland, Ryan had his most fruitful years. He earned three Pro Bowl nods and was in the running for the United Press International NFL MVP in 1965.

In 1964, Ryan led the Browns to their fourth NFL Championship over Johnny Unitas and the Baltimore Colts. He led the NFL with 25 touchdown passes and also had 2,404 passing yards. Ryan then threw for 18 touchdowns in 1965 and 29 touchdowns in 1966.

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He played for the Browns through the 1968 season and then was a reserve for the Washington Redskins in 1969 and 1970.

When Ryan’s career was over, he went back to Rice to receive his Ph.D. He went on to teach math at Case Western Reserve in Cleveland and later Yale and Rice. He was also credited with helping create an electronic voting system that helped modernize the U.S. House of Representatives.

He is survived by his wife Joan. They celebrated their 65th wedding anniversary last year.

The Associated Press contributed to this report.

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