SEDALIA, Mo. — Former State Sen. James "Jim" Mathewson, who was the longest-serving president pro tem in the Missouri Senate, died Monday at his home in Sedalia. His family said he died of cancer at the age of 83.

Mathewson, a Democrat, was first elected to the Missouri House in 1974 and was reelected twice to that chamber. He was elected to the Missouri Senate in 1980 and served there until 2005, when he retired because of term limits.

Mathewson was elected in 1989 as president pro tem, the top leadership post in the chamber. He served in that capacity for eight years, during the administration of Gov. Mel Carnahan.

After his legislative career, Mathewson was appointed to the Missouri State Fair Commission and the Missouri Gaming Commission.

Funeral arrangements are pending with Heckart Funeral Home in Sedalia.