The heroine of the story, Lou Witt, abandons her sterile marriage and a brittle, cynical post-First World War England. Her sense of alienation is associated with her encounter with a high-spirited stallion, the St Mawr whose name provides the title for this tale. She eventually settles in a remote ranch set high in the mountains of New Mexico, near Taos. Lawrence wrote most of this brief novel whilst spending five months of the summer of 1924 at what is now known as the D. H. Lawrence Ranch, a property which he and wife, Frieda, acquired from Mabel Dodge Luhan earlier that year.