After the Italian army invaded Cyrenaica in 1913 as part of their wider invasion of Libya, the Senussi Order fought back against them.

[2] Pressured to do so by the Ottoman Empire, Ahmed had pursued armed attacks against British military forces stationed in neighbouring Egypt.

[2] Instead he established a tacit alliance with the British, which would last for half a century and accord his order de facto diplomatic status.

As part of the Accord, he was given a monthly stipend by the Italian government, which agreed to take responsibility for policing and administration of areas under Senussi control.

Doing so would contravene the al-Rajma Agreement and would damage relations with the Italian government, which opposed the political unification of Cyrenaica and Tripolitania as being against their interests.

[8] Following the agreement, Idris feared that Italy — under its new Fascist leader Benito Mussolini—would militarily retaliate against the Senussi Order, and so he went into exile in Egypt in December 1922.

Badoglio's successor in the field, General Rodolfo Graziani, accepted the commission from Mussolini on the condition that he was allowed to crush Libyan resistance unencumbered by the restraints of either Italian or international law.

Beginning in the first days of Italian colonization, Omar Mukhtar, a Senussi sheik, organized and, for nearly twenty years, led Libyan resistance efforts.

Soon afterward, the colonial administration began wholesale deportation of the people of the Jebel Akhdar to deny the resistance to the support of the local population.

The forced migration of more than 100,000 people ended in concentration camps in Suluq and El Agheila, where thousands died in squalid conditions.

[14][15] According to Knud Holmboe, tribal villages were being bombed with mustard gas by the spring of 1930, and suspects were hanged or shot in the back, with an estimated thirty executions taking place daily.

[16] Angelo Del Boca estimated between 40,000 and 70,000 total Libyan deaths due to forced deportations, starvation and disease inside the concentration camps, and hanging and executions.

[20] Typhus and other diseases spread rapidly in the camps, as the people were physically weakened by forced labor and meager food rations.

In March 1937 Mussolini made a state visit to Libya, where he opened a new military highway running the entire length of the colony (the Via Balbia).

These colonists were shipped primarily to Sahel al-Jefara in Tripolitania and the Jebel Akhdar in Cyrenaica, and given land from which the indigenous inhabitants had been partially removed during the colonial war in the 1920s.

The 22,000 Libyan Jews were allowed to integrate in the society of the "Fourth Shore", but after summer 1941, with the arrival of the German Afrika Korps, they began to be moved to internment camps under Nazi SS control.

Under the terms of the 1947 peace treaty with the Allies, Italy, which hoped to maintain the colony of Tripolitania, (and France, which wanted the Fezzan), relinquished all claims to Libya.

Omar al-Mukhtar's final years were depicted in the movie Lion of the Desert (1981), starring Anthony Quinn, Oliver Reed, and Irene Papas.

In August 2008 the two nations signed a treaty of friendship in which US$5 billion in goods and services, including the construction of the Libyan portion of the Cairo-Tunis highway, would be given to Libya to end any remaining animosity.

[31][32][33] In exchange, Libya would take measures to combat illegal immigration coming from its shores and boost investments in Italian companies.

On 26 September 2011, Italian energy company Eni announced it had restarted oil production in Libya for the first time since the start of the 2011 Libyan civil war.