Major General Cassius Marcellus Clay was an American planter, politician, military officer and abolitionist who served as the United States ambassador to Russia from 1863 to 1869. Born in Kentucky to a wealthy planter family, Clay entered politics during the 1830s and grew to support the abolitionist cause in the U.S., drawing ire from fellow Southerners. A founding member of the Republican Party in Kentucky, he was appointed by President Abraham Lincoln as the U.S. minister to Russia, where Clay is credited with influencing Russian support for the Union during the American Civil War.

Henry Clay Sr. was an American lawyer and statesman who represented Kentucky in both the U.S. Senate and House of Representatives. He was the seventh House speaker as well as the ninth secretary of state. He unsuccessfully ran for president in the 1824, 1832, and 1844 elections. He helped found both the National Republican Party and the Whig Party. For his role in defusing sectional crises, he earned the appellation of the "Great Compromiser" and was part of the "Great Triumvirate" of Congressmen, alongside fellow Whig Daniel Webster and Democrat John C. Calhoun.