Complex sentence: He became a friend of D. H. Lawrence, and traveled with him and Frieda von Richthofen in Mexico; he much later in 1951 wrote on Lawrence, while he and his partner Willard Johnson are portrayed in Lawrence's "The Plumed Serpent".
Split into simpler sentences: He became a friend of D. H. Lawrence, and traveled with him and Frieda von Richthofen in Mexico. He and his partner Willard Johnson are portrayed in Lawrence's "The Plumed Serpent".