When did Walt Whitman first publish Treasure Island by Robert Stevenson?

Walt Whitman did not publish "Treasure Island"; it was actually written by Robert Louis Stevenson. "Treasure Island" was first published as a book in 1883. Whitman, an American poet, is known for his work "Leaves of Grass," which was published in 1855. The two authors belonged to different literary spheres and were contemporaries but did not collaborate on any works.