His red wheelbarrow might be the most famous gardening tool in American poetry, but Thaddeus Marshall, the man who inspired William Carlos Williams’s classic poem “The Red Wheelbarrow,” had been forgotten by history—until now.

A note in a 1933 anthology indicated Williams had seen the wheelbarrow “outside the window of an old negro’s house on a backstreet”; later, in 1954, the poet mentioned Marshall by last name in an essay for Holiday magazine: “I liked that man, and his son Milton almost as much . . . I suppose my affection for the old man somehow got into the writing.”

But Marshall remained an elusive figure until William Logan, a professor at the University of Florida, tracked down a 1920 census and determined that the old man could only by Thaddeus Marshall, then a 69-year-old widower who lived at 11 Elm Street in Rutherford, N.J., with his son Milton, just a few blocks from Williams’s house. The chickens and the wheelbarrow are long gone now, but a fire insurance map from 1917 shows a large chicken coop on the property.

Marshall’s great-granddaughter Teresa Marshall Hale—now 69 herself—grew up in the house on Elm Street and says she knew about Williams (he was a doctor as well as a poet and delivered Hale’s father when he was born and signed her grandmother’s death certificate), but had no idea her grandfather had made his way into Williams’s poetry.

On July 18, a stone will be laid on Marshall’s otherwise unmarked grave, where he was buried in 1930.