Graziani played an important role in the consolidation and expansion of Italy's empire during the 1920s and 1930s, first in Libya and then in Ethiopia. He became infamous for harsh repressive measures, such as the use of concentration camps, that caused many civilian deaths, and for extreme measures taken against the native resistance such as the hanging of Omar Mukhtar. Due to his brutal methods used in Libya, he was nicknamed "Il macellaio del Fezzan" ("the butcher of Fezzan"). In February 1937, after an assassination attempt against him during a ceremony in Addis Ababa, Graziani ordered a period of brutal retribution now known as Yekatit 12. Shortly after Italy entered World War II he returned to Libya as the commander of troops in Italian North Africa but resigned after the 1940–41 British offensive routed his forces.