Updated

Rep. John Conyers, D-Mich., announced his immediate retirement on Dec. 5 following a wave of sexual harassment allegations.

Conyers, 88, was the longest continuously serving lawmaker in the House at the time of his retirement.

Here’s a look at the 15 longest-serving U.S. senators and congressmen.

John Dingell - 59 years

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Rep. John Dingell Jr., D-Mich., was in office from 1955 to 2015. (Reuters/Rebecca Cook)

Rep. John Dingell Jr., D-Mich., was first elected in a special election to fill a seat which was left empty when his father, Rep. John Dingell Sr., died, according to his House biography. Dingell served in the Army during World War II and was a Wayne County assistant prosecutor before he was elected to public office.

Dingell was in office from Dec. 13, 1955 to Jan. 3, 2015 and remains in the public eye. He is active on Twitter with an account boasting of more 196,000 followers.

Robert Byrd - 57 years

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Robert Byrd. D-W.V., served in the Senate longer than any other person. (Reuters/Kevin Lamarque)

Robert Byrd’s political career included stints in both congressional chambers -- and he holds the record for the longest term in the Senate.

Byrd, D-W.V., served in the House for six years before spending 51 years in the Senate until his death on June 28, 2010, his congressional biography stated. He was 92 years old when he died.

Carl Hayden - 56 years

Before he was elected to Congress, Carl Hayden’s resume included being commissioned as a major in the Army during World War I and spending five years as the sheriff of Maricopa County, Ariz., according to his congressional biography.

Hayden, D-Ariz., was in the House of Representatives from Feb. 19, 1912 to March 3, 1927, and he later served 41 years in the Senate. He was 94 years old when he died in 1972.

Daniel Inouye - 53 years

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Daniel Inouye, D-Hawaii, served nearly 50 years in the Senate prior to his death in 2012. (Reuters/Joshua Roberts)

A World War II veteran, Daniel Inouye “volunteered as a private in 1943 and retired after much action as a captain in 1947,” according to his congressional biography. Inouye, D-Hawaii, served in the House from Aug. 21, 1959 to Jan. 3, 1963, before serving nearly 50 years in the Senate until his death in 2012.

The lawmaker was a 2000 recipient of the Congressional Medal of Freedom and a 2013 recipient of the Presidential Medal of Freedom.

Jamie Whitten - 53 years

Rep. Jamie Whitten, D-Miss., was first elected through a special election to fill a House seat left empty by Wall Doxey. He was in office from Nov. 4, 1941 to Jan. 3, 1995, according to his congressional biography.

Whitten was chairman of the House Committee on Appropriations from 1979 to 1993. After leaving office in 1995, he died later that year at age 85.

John Conyers - 52 years

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Rep. John Conyers, D-Mich., stepped down from Congress after serving for nearly 53 years. (Reuters/Jonathan Ernst)

Prior to retiring on Dec. 5, Rep. John Conyers represented Michigan’s 13th Congressional district. Conyers, 88, was elected to his 26th consecutive term in 2014 -- a win that made him the first African American to hold the distinction as Dean, or the most senior member of Congress, according to his website.

The Democratic representative faced pressure to resign after reports emerged that he allegedly made unwanted sexual advances toward multiple different women. His settlement with Marion Brown, a former staffer, came to light in November.

Carl Vinson - 50 years

Rep. Carl Vinson, D-Ga., was in Congress for nearly 51 years and was the first person to serve in the U.S. House of Representatives for more than 50 years.

Vinson, who was born in Georgia in 1883, served in Congress from 1914 to 1965. He helped modernize the U.S. Navy. Eventually, the Navy vessel, the USS Carl Vinson, was named after him.

He died at the age of 97 in 1981.

Emanuel Celler - 49 years

Rep. Emanuel Celler, D-N.Y., was elected to the House in 1922 when he was just 34 years old. Forty-two years later, he became Dean of the House.

Celler, who was born in 1888 in Brooklyn, became the chairman of the Judiciary Committee in 1949 and was one of the authors of the 1964 Civil Rights Act, according to his obituary in the New York Times.

He died in 1981 at the age of 92.

Sam Rayburn - 48 years

Rep. Sam Rayburn, D-Texas, was born in 1882 and was elected to the Texas House of Representatives in 1906, serving the state’s 4th Congressional district from 1907 to 1913. Afterward, he became the 43rd Speaker of the House. He served in the position from 1913 until his death in 1961.

Rayburn was also the House majority leader in 1937 and chairman of the National Democratic Convention.

Sidney Yates - 48 years

Rep. Sidney Yates, D-Ill., died in 2000 at the age of 91. One of his greatest accomplishments while serving as a congressman was pushing for legislation that established the National Endowment for the Arts in 1965.

He was elected to Congress in 1948 and served until 1999.

Strom Thurmond - 46 years

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Sen. Strom Thurmond, R-S.C., turned 100 years old while in the Senate, becoming the oldest person ever to serve in that chamber. (Reuters/Kevin Lamarque)

Sen. Strom Thurmond of South Carolina was a lifelong lawmaker -- serving as a state senator and governor in the Palmetto State before his stint in Washington, D.C. And when he turned 100 years old in 2002, he became the oldest person ever to serve as a senator.

Thurmond joined the Republican Party in 1964 and ran for president as the States’ Rights Democrat candidate in 1948, winning four states. Thurmond holds the Senate record for the longest individual speech with his filibuster of the 1957 Civil Rights Act, according to his Senate biography.

He was in office from Nov. 7, 1956 to Jan. 3, 2003. He died in June 2003.

Wright Patman - 47 years

Rep. Wright Patman, D-Texas, served in the House for 47 years until his death on March 7, 1976.

Patman, who was 82 when he died, served in World War I as a private and machine gun officer, according to his House biography. He was first elected to Congress in 1928. He led an effort to impeach former Treasury Secretary Andrew Mellon and was chairman of the House’s banking committee for some time.

Ted Kennedy - 46 years

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Sen. Ted Kennedy was known as the "liberal lion of the Senate." He died in 2009 at 77 years old. (Reuters/Mike Segar)

Sen. Edward “Ted” Kennedy, D-Mass., died on Aug. 25, 2009. At the time, he was 77 years old and partially through his 46th year as a U.S. senator. Kennedy was battling brain cancer when he died.

Known as the “liberal lion of the Senate,” Kennedy was passionate about voting rights, education, immigration reform, minimum wage, tackling the AIDS crisis and equality for minorities, women, LGBT and disabled Americans, according to his biography.

Kennedy was the younger brother of former President John F. Kennedy.

Charles Rangel - 46 years

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Rep. Charlie Rangel, D-N.Y., was censored by the House Ethics committee. (Reuters/Hyungwon Kang)

Rep. Charlie Rangel, D-N.Y., was in office until Jan. 3, 2017; he did not seek reelection in 2016.

Rangel, now 87, was censored by the House Ethics Committee in 2010 for financial misconduct. He was found guilty by the committee of 11 violations.

While in the House, Rangel headed many committees for a period of time, including the Ways and Means committee and Joint Committee on Taxation, according to his archived House biography.

Joseph Gurney Cannon - 46 years

Former House speaker Joseph Gurney Cannon, R-Ill., was in Congress for a cumulative 46 non-consecutive years.

As Speaker and chairman of the House Rules committee, Cannon was known for ruling “Congress with an iron fist,” according to a House biography, and had tight control over the legislative schedule and floor debates. He was given the nickname “Czar Cannon” for his leadership style. He was also nicknamed “Uncle Joe.”

Cannon died in 1926 at the age of 90. He left office in 1923.