 During World War II , Miller served as part of a bomber crew that participated in the destruction of the ancient Roman Catholic monastery at Monte Cassino , Italy founded by St. Benedict in the 6th century . This experience impressed him enough to write , a decade later , the short story " A Canticle for Leibowitz " about an order of monks whose abbey springs from the destroyed world around it . The story , which would evolve into " Fiat Homo " — the first part of the novel — was published in the April 1955 edition of The Magazine of Fantasy and Science Fiction ( F & SF ) . Although not originally intended as a serialization , the saga continued in " And the Light Is Risen " , which was published in August 1956 ( also in F & SF ) . That work would later grow into " Fiat Lux " . It was while writing the third " novelette " , " The Last Canticle " , for magazine publication in February of the following year that Miller realized he was really completing a novel : " Only after I had written the first two and was working on the third did it dawn on me that this isn 't three novelettes , it 's a novel . And I converted it . " 
