NEW YORK — Robert D. Richardson, a prize-winning historian known for his elegant and authoritative biographies of such leading American thinkers as William James and Ralph Waldo Emerson, has died.

His friend Arlo Haskell told The Associated Press that Richardson died June 16 after sustaining head injuries in a fall. Richardson, husband of the Pulitzer Prize-winning writer Annie Dillard, turned 86 just days before his death.

Richardson won the Bancroft Prize in 2007 for “William James: In the Maelstrom of American Modernism.” In 1996, his “Emerson: The Mind On Fire” won the Francis Parkman Prize and was a National Book Critics Circle finalist.

“Henry David Thoreau: A Life of the Mind” was published in 1986 and had a more personal impact on his life. The book’s fans included Dillard, who sent him a fan letter and eventually married.