Born in Perugia, although he lived in Rome for most of his life, Orelli came from a military family whose members had served in various Italian conflicts since 1849.

During World War II, despite his aversion to Nazi Germany and fascism, he was forced to work as an artillery director in Italy.

In his later years, he was active in urging others not to forget the lessons learned after the first World War, and in 2003 he was made a Grand Officer in the Order of Merit of the Italian Republic.

Orelli was born in Perugia on 23 December 1894, although his family soon moved to Rome to be nearer to an aunt that operated a local tavern.

His maternal grandfather, Thomas, helped defend Perugia against Austrian mercenaries in 1849, while Carlo's father served in the Italian Abyssinian campaign during the Scramble for Africa in the 1880s.

[4] Entrenched with the 320 Infantry Regiment, he served as a foot soldier within the Italian Army and engaged in combat activity in the trenches near Trieste, which was the main battleground in the east.

[5] In his autobiography, Orelli went into great detail about his experiences, including the large number of casualties that he witnessed during his time in the trenches and widespread illiteracy among the peasant soldiers.

[5] In order to mentally prepare himself for an attack, overcome this fear and keep a clear head, he forced himself to purge his mind of all thoughts of home and family.

[1][7] In his later years, he was active in telling tales of his experiences in the First World War, imploring those who listened to "not forget our sacrifice.