But the Vaughan portrait is not the most famous, nor are the approximately 100 other portraits Stuart eventually painted of Washington. It is the Athenaeum portrait, a work he began in 1796 at the bequest of Washington’s wife Martha, that has seared a specific image of the first president into the collective national consciousness. An engraving of Washington’s portrait as it appears in the Athenaeum version has been used for the one-dollar bill since the early 1900s (although modified slightly, so that Washington faces the other way). The painted version can be found on the walls of the National Portrait Gallery in D.C. and the Boston Museum of Fine Arts; the printed version appears in wallets and tip jars.

Stuart never finished the Athenaeum portrait, but he saw some power in the face he’d painted. He asked the president if he could keep the unfinished version to use as a basis for further portraits. A spendthrift who was perpetually in debt, Stuart used his later Washington portraits modeled on the Athenaeum version to earn money, capitalizing on a market hungry for images of the country’s beloved leader and eager for works by the now-celebrated painter.

Some of Stuart’s later renown, McEvansoneya notes, can be explained by “having been, effectively, the court portraitist to the first five U.S. presidents.” But he says Stuart’s “flashy fluid brushwork and richness of color” also deserves some credit—techniques that were later used in “swagger portraits,” a name coined for the grand, idealized portraits of the 18th- and 19th-century rich and famous. Stuart’s portraits of other members of the American elite, including Thomas Jefferson and James Madison, tend toward this style.

But what is it about the Athenaeum portrait in particular—an unfinished painting of an older Washington—that is so persistent?