The 15-cent stamp is a tribute to a leading American statesman and orator, Henry Clay (1777–1852). Clay studied law in Virginia, and after passing the bar in 1797, he moved to Lexington, Kentucky. He eventually represented that state in the U.S. House of Representatives and the U.S. Senate.
While serving in the House, Clay was chosen as one of the commissioners to negotiate the Treaty of Ghent, which ended the War of 1812. A devote Federalist, he advocated programs that expanded commerce and industry, especially canals, railroads, and banks. He was known as the 'Great Pacifier' because of his success in brokering compromises on the slavery issue in 1820 and 1850. Clay put together legislation that would eventually be known as the 'Compromise of 1850'. The Compromise, a response to sectional demands for and against slavery, forestalled the Civil War for ten years. That decade gave the North time to prepare economically and politically for the inevitable. In 1957 a Senate committee chaired by John F. Kennedy named Clay as one of the five greatest senators in American history.
The 15-cent olive green stamp was issued May 24, 1903, only in sheet format printed from plates of two hundred and four hundred stamps and sold in panes of one hundred stamps with gauge 12 perforations. The stamp was designed by R. Ostrander Smith from an engraving by Alfred Sealey. The engravers were Marcus W. Baldwin (portrait), Robert F. Ponickau (frame), and George U. Rose Jr. and Lyman F. Ellis (lettering and numerals).
The 15-cent stamp was primarily used to pay multiples of the foreign five-cents-per-half-ounce letter rate in effect until Oct 1, 1907. The stamps were also used on larger domestic fourth-class parcels. A single 15-cent stamp paid the foreign five-cents-per-half-ounce plus the ten-cent registry fee. Multiples are also found paying the foreign samples and merchandise rates.