Operation Crusader was an offensive of the British Commonwealth in late 1941 against the German-Italian forces in Libya, which resulted in relieving the siege of Tobruk.
Since his arrival in North Africa in early 1941, the German General Erwin Rommel had led a successful offensive against the British with his German expeditionary force - Afrika Korps, regaining through daring maneuvers the eastern region of Libya - Cyrenaica - lost previously by the Italians. Only the port of Tobruk had remained isolated behind the Axis lines, tenaciously defended by the Australians, then replaced by the British, Poles and Czechoslovaks.
By Stephen Kirrage (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/deed.en)], via Wikimedia Commons
In June 1941, the British Army launched the failed Operation Battleaxe, aiming the relief of Tobruk and chasing the Axis forces from eastern Libya.
In autumn, a new offensive, named Operation Crusader, was in preparation. The British Eighth Army relied, in addition to the British forces, on divisions from India, New Zealand, and South Africa. Unlike the German and Italian forces, it was better supplied and had come to numerical superiority in key aspects such as tanks and aircraft.
According to the British plan, XIII Corps was to engage the Axis forces from the border with Egypt, while XXX Corps, which had most tanks, would attack in depth on the southern flank, to make contact with the beleaguered forces from Tobruk.
On November 18, 1941, the Commonwealth forces commenced the attack, the British armor from XXX Corps encountering soon opposition from the German Afrika Korps and Italian Armored Division Ariete. The superior tactics used by Rommel counterbalanced the higher number of British tanks, the Axis units repelling the attack of the British 7th Armoured Division, which was the spearhead of XXX Corps.
Bundesarchiv, Bild 183-1982-0927-502 / Moosmüller / [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/de/deed.en)], via Wikimedia Commons
Encouraged by the favorable outcome, Rommel sent Afrika Korps with the few remaining operational tanks to counterattack towards the border with Egypt. The Eighth Army's artillery, well positioned at Sidi Omar, stopped the panzers, reducing the German offensive capability at a dangerously low level.
Meanwhile, the fightings continued near Tobruk, and the Axis forces were in a dangerous situation due to the losses, poor supply and the vulnerability of the communications line. Under these circumstances, Rommel decided to withdraw his forces to the Gazala line, west of Tobruk.
Tobruk was finally relieved. The Eighth Army attacked the Gazala line a few days later, which prompted Rommel to withdraw his forces once again, this time up to El Agheila, where the much shorter communications line facilitated the supply and recovery of his weakened army. The first victory of the British Commonwealth against Erwin Rommel's Afrika Korps had been just accomplished, but "the Desert Fox" was preparing his reply.