John Neagle. Pat Lyon at the Forge, 1829. Oil on canvas, unframed: 94½ x 68½ in. Museum of Fine Arts, Boston. Gift of the Lyon Family, 1842.1.

Declared by Congress in 1894, the first Monday in September honors the nation’s workers and their contributions to the wellbeing of the country. Its roots are seen to date to the 1886 Haymarket Riot in Chicago.