Robert Dickinson Allen, professor and Confederate officer, was born on January 19, 1836, in Washington, D.C. He was the son of Gen. Robert Thomas Pritchett Allen (1813–1888) and Julia Ann Dickenson. Gen. R.T.P. Allen was a distinguished graduate of West Point, became president of the Kentucky Military Institute, and established the Bastrop Military Institute (see TEXAS MILITARY INSTITUTE, AUSTIN). He also recruited the Seventeenth Texas Infantry Regiment of John G. Walker's Texas Division in Bastrop County in January of 1862. General R.T.P. Allen later moved to Florida, where he drowned in the Kissimmee River on July 8, 1888.
Robert Dickinson Allen's early life revolved around his father's career. He was born in Washington D.C. and then lived in both Kentucky and Texas. He attended his father’s Kentucky Military Institute and studied medicine at the University of Louisville. By 1860 he was living in Bastrop, Texas, and worked as a math professor at Bastrop Military Institute. His first wife was Laura Adelaide Sims (1842–1885) of Clarksville, Texas. They married in Bastrop on June 14, 1858. They had four children.
After the outbreak of the Civil War, Robert Dickinson Allen became captain of Company A of the Seventeenth Texas Infantry. He enlisted for duty as a captain at Camp Terry on March 7, 1862 and was promoted to major on April 2, 1862. He served as major for a little over a year before tendering his resignation on July 15, 1863, and officially resigned from duty due to ill health on August 26, 1863.
After his son's resignation, General R.T.P. Allen moved his family from Texas back to Kentucky where he worked as a teacher and eventually became superintendent of the Kentucky Military Institute. After R. D. Allen's wife Laura died in Kentucky in 1885, he married Minnie Green of Louisville, Kentucky. His eldest son, Robert Sims Allen, would later become commandant of cadets at the Kentucky Military Institute.
Allen eventually moved to Harris County, Houston, Texas, where he died on May 6, 1913.