One likely inspiration for A Distant Trumpet as a historical novel of the Southwest is Willa Cather's Death Comes for the Archbishop (1927), whose fictional Bishop Latour representing the real-life Juan Bautista Lamy (18141888) would provide Horgan with the subject of his 1975 biographical study Lamy of Santa Fe. The 1930s, the decade of Horgan's emergence on the literary scene, was the heyday of the historical novel; this trend continued through the 1940s and in the middle 1950s MacKinlay Kantor's Civil War-era novel Andersonville made the best seller lists for two consecutive years.

Because General Alexander Quait is based roughly upon the career of General George Crook (1829-1890) and Rainbow Son represents Geronimo (1829?-1909), Horgan duly appends a bibliography of nonfiction sources that gave him pleasure and instruction for the "task of many years" which the novel represents. These include such works as On the Border with Crook (1891) by...