Philip Levine, poet of the American working class and U.S. Poet Laureate from 2011-2012, died on Saturday at 87 at his home in Fresno, Calif., according to the San Francisco Chronicle. The cause of death was pancreatic cancer.

Born in 1928 in Detroit, Mich, Levine became one of America’s most famous poets writing about the lives of working class Americans and thinking deeply about the nature and meaning of work itself. Perhaps his best known poem, “They Feed They Lion,” imagines a figurative lion, an embodiment of anger and power, grown from the work and energy of average people:

Out of the gray hills
Of industrial barns, out of rain, out of bus ride,
West Virginia to Kiss My Ass, out of buried aunties,
Mothers hardening like pounded stumps, out of stumps,
Out of the bones' need to sharpen and the muscles'
to stretch,
They Lion grow.

Working in factories in his youth gave Levine the material for his mature poetry. He earned his MFA at the University of Iowa Writers' Workshop in the 1950s and went on to mentor countless younger poets as a professor at California State University at Fresno, New York University, Columbia, and many other institutions.

Long published by Knopf, Levine won the Pulitzer Prize in 1995 for his collection The Simple Truth. His most recent collection is News of the World (2009). Other books include the poetry collections The Mercy (1999) and Breath (2004), and the autobiographical volume The Bread of Time (1994).