In addition to his textbooks, Davis was author of "Fallen Guidon: The Saga of Confederate General Jo Shelby's March to Mexico", published first in 1962 and again in 1995, a year after Davis; death, by Texas A&amp;M University Press. After the Battle of Appomattox Court House in April 1865, some Confederates remained steadfast to what is sometimes known as the Lost Cause. One particular group led by General Joseph O. Shelby of Missouri, followed its cavalry flag, or guidon, south with the goal of planting an imperial colony in Mexico. Shelby declared that he and his men preferred exile from the United States to submission to the Union Army. Shelby was motivated by the report that U.S. President Abraham Lincoln wanted the Habsburg emperor Maximilian, I, driven out of Mexico, and Shelby proposed to join forces with Benito Juarez for that purpose. He expected to prevail and spread the Lost Cause to a new land. Davis was a descendant of one of Shelby's men.