Artist Allyn Cox created murals in the U.S. Capitol over two decades from 1952 to 1972. He completed and restored the Frieze of American History and restored the Apotheosis of Washington in the Rotunda. He also designed murals for three first-floor corridors in the House wing, now called the Cox Corridors, and completed two of them before his death.

Allyn Cox was born in 1896 in New York City; his father, Kenyon Cox, was an eminent muralist and his mother was a painter. After studying at the National Academy of Design and at the American Academy in Rome, he began specializing in murals and portraiture. Cox belonged to various professional organizations and in some served as an instructor, trustee, fellow or president.

In 1952 Cox was selected to finish the Frieze of American History in the Capitol Rotunda begun in 1878 by Constantino Brumidi and continued by Filippo Costaggini after Brumidi’s death. He designed and painted three scenes that filled a gap that had existed since 1889. He also restored the original portion of the frieze, and in 1959 he restored Brumidi's Apotheosis of George Washington in the eye of the Dome by repainting it.

Cox also painted the portrait of Henry Clay for the Senate Reception Room in 1958; 16 years later he depicted America's first moon landing in the Brumidi Corridor. In 1969 he began the research and preliminary sketches for the first corridor, the Hall of Capitols, on the first floor of the House wing (now known as the Cox Corridors). He started painting in February 1973 and completed it in July 1974. In painting the Great Experiment Hall, which was completed shortly before his death in 1982, he was assisted by Cliff Young. Cox also created drawings for the Westward Expansion corridor, which was painted by Evergreene Painting Studios in 1993 based on his approved design.