Cleofas Calleros, historian and community leader in El Paso, was born on April 9, 1896, in Río Florido, Chihuahua, Mexico, to Ismael and Refugia (Perales) Calleros. In 1902 the family immigrated to El Paso to farm, and Calleros enrolled in Sacred Heart School, from which he graduated as valedictorian in 1911. He later attended Draughton Business College. Poverty forced him to work throughout his adolescence; one of his first jobs was in a print shop, where he learned how to print and bind books. In October 1917 Calleros lied about his citizenship in order to serve in World War I. He became a naturalized citizen in June 1918. He later spent forty years organizing free citizenship-preparation classes for thousands of immigrants. Calleros served in the Army of Occupation in Germany in 1919. He was wounded in action and awarded the Purple Heart. He was a member of the United States Army Officers Reserve Corps from 1920 to 1938. In April 1918 he married Benita Blanco, with whom he had one daughter. He worked as a border representative for the Department of Immigration of the United States Catholic Conference for more than twenty years.
Calleros won several awards for his writing, including the Daliet Award and trophies for four years (1925–28) that he spent gathering materials for the Texas Centennial in 1936. In 1952 he shared first prize and the award of merit of the American Association for State and Local History with theEl Paso Times, for which he had produced feature articles dealing with the history of West Texas. In 1954 he collaborated with Marjorie F. Graham on El Paso-Then and Now, a book based on his series of newspaper articles focusing on El Paso in 1896. He collected the historical data and coauthored with Dr. Ángel Alcázar de Velasco of Madrid, Spain, the book Historia del Templo de Nuestra Señora de Guadalupe (1953). It took numerous years to write, illustrate, and hand-print the book on a "workworn Chandler job press." The work includes information on early settlements in Texas. Carlos E. Castañeda wrote the introduction, and José Cisneros produced twelve illustrations of early Franciscan missionary and expeditionary motifs for it. The unique format of the 200-page limited edition made it a historic "book of the century." Rich printing materials were used, and great care was taken in producing a special copy in vellum for Pope John XXIII. Others were embossed in silk, imitation parchment, and Florentine paper. The borders of each page were of a different design. The entire book was bound in Mexican leather, and a seventeenth-century style of printing was used.
Beginning in the 1920s Calleros became involved in a variety of community activities to clear slums, to improve his old southside neighborhood, and to enrich the arts. He also helped organize the El Paso Boy's Club, the League of United Latin American Citizens in El Paso, the Chihuahua State Historical Society, and the Western History Association. Calleros was also a founding member of the first Knights of Columbus chapter in Texas-Council 638-about which he wrote a short history on the occasion of its seventieth anniversary. As a member of the council, he helped establish a boys' center and organized many other councils in the state. His efforts with the Knights of Columbus were honored through his investiture as a Knight Commander of St. Gregory the Great. He was also designated a Knight of the Order of Isabella by the Spanish Government for his work on Spanish history in the Southwest. In addition, Calleros was awarded an honorary master of fine arts degree by New Mexico State University and an honorary doctorate in history by the University of New Mexico. Calleros died on February 22, 1973, and was buried at Fort Bliss National Cemetery with military honors. His daughter later donated his papers to the University of Texas at El Paso Special Collections and Archives.