Cesar Vallejo is one the greatest poets of the twentieth century, his monument being the book-length sequence Trilce - one of only two collections of his poetry published during his lifetime, the other being Los heraldos negros (The Black Heralds). After Trilce Vallejo wrote stories, essays, a novel, and several plays, but did not collect any of his subsequent poems for book publication. Since his death, these poems have usually been referred to as the Poemas humanos after the title of one of the posthumous volumes.