Renato Ziggiotti failed to join the army during World War I, so in 1917 he just studied theology, which focused on the nature of God and religious belief.
When World War I began in 1914, Ziggiotti was enlisted in the army, as were many other Salesian young men. In 1917 he was wounded in an arm and remained in the hospital for several months, a time he used to study theology. In April 1919 he terminated in the army with the grade of Captain and returned to Padua to continue priestly studies, to be ordained on December 8, 1920. 
