Gao Lan was a military general serving under the warlord Yuan Shao during the late Han Dynasty period of Chinese history. He fought in many battles and was respected as a brave man by Yuan. He defected to Cao Cao's side after Yuan's defeat in the Battle of Guandu.
Serving Yuan Shao
Cao Cao and Yuan Shao faced off with each other at the Battle of Guandu. Yuan dispatched Chunyu Qiong and others to guard Wuchao, where Yuan kept his food supplies. Cao personally led a raid on Wuchao with a small force, disguised as Yuan's men, to debilitate Yuan.
Zhang He, one of Yuan's generals, said to his lord: "Duke Cao's armies are elite, they would surely defeat Chunyu Qiong. After Chunyu Qiong is defeated, the army will scatter. Instead, let me and Gao Lan reinforce Wuchao." Yuan's advisor Guo Tu remarked, "Zhang He's plans are bad. Instead, let us attack the original source (referring to Cao Cao's main camp), power will surely return to our side. This explanation is why reinforcements should not be sent." Zhang then replied: "Duke Cao's encampment is solidified, it is too hard to uproot. If Chunyu Qiong's camp is captured we will be depleted and captured in turn. Cao will be too enveloped in taking Wuchao to leave a guard. I entreat you to attack his main camp."
Yuan Shao did not send the reinforcements to aid Chunyu Qiong, instead he sent five companies under Zhang He and Gao to attack Cao's main army. Through a ruse involving Xu Chu and Zhang Liao, they beat Chunyu Qiong out of the granaries, and Yuan was led to believe that the granaries had been successfully defended.
Yuan Shao's army, which was attacking Cao's main camp, was presently being attacked on three sides, and when the men came back from Wuchao, they came up on Yuan's rear, surrounding the five companies. However, Zhang He and Gao escaped, but altogether Yuan Shao's army was defeated. When Chunyu reached the main army, which was decimated, he was brought in to see Yuan Shao. Yuan railed at him, asking why the defenses of the granary had been sparse. Chunyu's men told Shao that Chunyu had been intoxicated that night, and Chunyu Qiong was executed forthwith.
Guo Tu was ashamed and plotted against Zhang He and Gao, and said to Yuan Shao, "Zhang He and Gao Lan were glad when your armies were defeated." He was asked how he knew this and thus replied, "They have long wished to defect to Cao Cao, so when you put them on this duty, they did not try their best and brought on this disaster." Yuan then sent a messenger to recall and interrogate them, but Gao knew of the plans ahead of time and when the messenger came to recall them, he killed him and both himself and Zhang truly defected to Cao, lest they be destroyed.
Serving Cao Cao
Zhang He and Gao gathered their troops and set off for Cao Cao's camp, who gave them permission to enter. Coming before Cao, Gao and Zhang disarmed themselves and bowed low obeisance. "Had Yuan Shao listened to you," Cao remarked, “he could have spared himself this defeat. Now you two have come to us like Weizi, who quit the dying Shang Dynasty, or Han Xin, who left Xiang Yu to serve the Han Dynasty.”
Cao awarded Gao the rank of adjutant general as well as appointing him Lord of Donglai. That was the last historical reference to him, but not in the historical fiction Romance of the Three Kingdoms by Luo Guanzhong (see below).
In fiction, after his surrender, his abilities were immediately put to use against his old lord, Yuan Shao. Xu You, who had also surrendered to Cao, advised a raid on Yuan's now demoralized camps. Gao offered to lead the attack and, along with Zhang, set off to raid the camp. Gao divided his forces into separate units and instructed his army to attack on all sides. At the appointed time, Gao led the attack on the camps and devastated Yuan Shao's army, demiating half of his men. The fighting went on until morning at which point Gao led his victorious troops back to his own camp. Yuan Shao, having suffered defeat at Guandu, retreated back to Ji Province.
Cao Cao started a follow up campaign against Yuan Shao at Ji Province in which Gao was an integral part. Initially, Cao's army suffered defeat at the hands of Yuan Shao's son, Yuan Shang, and was forced to retreat to the river. Cao ordered ten units divided in five pairs to assemble, and Gao was commander of the fifth. Yuan Shao indubitably followed and was defeated by Cao's counterattack. Predicting this outcome, Gao placed his troops in ambush along the road to Ji Province. Yuan Shao's defeated troops were spotted retreating along the road and once they came upon Gao, his men emerged from the left side of the road, while troops of Xiahou Yuan's sprung from the right, delivering severe injuries to the northern army and almost killing Yuan Shao himself.
Soon after the victory at Ji Province, word came of an attack being made on the capital of Xuchang by Liu Bei. Cao Cao, along with Gao, abound Ji Province for the time being to thwart Liu. Cao's army met Liu, but fatigued from their long march, were defeated in the first battle. To divide Liu's forces, Cao had Xiahou Dun attack Liu's camp, another unit attack a supply train, and Xu Chu attack Liu himself. Liu was thus defeated and forced into flight, and Cao ordered Gao to pursue and attack him. He set out and reached Liu's troops and Liu, horrified at Gao's arrival, attempted to take his own life, but his commander Liu Pi stopped him. Liu Pi then charged at Gao, but was cut down at the moment of engagement. Gao then ordered his troops to descend the hill and attack Liu Bei, but before they could he was distracted from rearward action. Gao turned to see the enemy commander Zhao Yun charging through his men, but before he could guard himself, Zhao reached Gao and impaled him on the spot.