There is a friendship that has become a core to the telling of many a tale about the three kingdoms. The unbreakable bond between the warlord-turned-Emperor Liu Bei and his two generals: Guan Yu and Zhang Fei.

Liu Bei of Zhuo once had to sell sandals and weave mats after his father died but a relative paid for a good education and he came to enjoy some of the finger things in life. Tall with long arms and big ears, good at keeping his feelings hidden, humble towards superiors and kind to others, merchant funding meant he could keep his own following and he loved to hang around with fighting men.

Two such men he became very close to. Guan Yu had been forced to flee his home in Hedong for reasons unknown and ended up meeting Liu Bei. He would, over his life, have a noted beard, be a keen study of The Commentary of Zuo, good to those beneath him but arrogant towards the gentry and unyielding. A young Zhang Fei was from Zhuo humble to scholars but brutal and violent to those beneath him.

The three of them were as brothers with Zhang Fei deferring to the older Guan Yu. When the Yellow Turban revolt allowed Liu Bei to lead his followers as soldiers, Guan Yu and Zhang Fei became his bodyguards. When Liu Bei was awarded his first official post as a magistrate, they shared command of the retainers with Guan Yu and Zhang Fei standing in attendance all day then all three sharing a bed when relaxing or sleeping.

The journey from small posts and subordinate command to Emperor would be a long journey with many moments of trouble. Liu Bei fled from his first post after violently beating an inspector, Zhang Fei costing the province of Xu by beating and possibly killing local official Cao Bao which sparked riots and an invite to a rival warlord to seize the province. Wounds in battle and many defeats, abandoned families in flight, mid-life crises of frustrated ambition and fat thighs, that is just Liu Bei.

Unfortunately for Guan Yu and Zhang Fei, we have a records gap and that includes the sense of bond. We know they were much admired as warriors with other warlords wanting them, the Cao adviser Cheng Yu famously remarking they were worth ten thousand men each but not shown how they gained that reputation. Fighting across the north, the central plains then south and west before finding a home and their faction having a poorly resourced records department have not helped. So what glimpses do we have of the friendship?

In 200, the friends were separated. Liu Bei rebelled a tried to take his old base of Xu but when Cao Cao arrived his position collapsed, Liu Bei (and presumably Zhang Fei) fled north to Yuan Shao but Guan Yu was captured as Xiapi fell. Cao Cao was an admirer of Guan Yu and treated him well but got the sense Guan Yu would not stay so sent Zhang Liao as an intermediary to ask, Guan Yu explained (translation Yang Zhengyuan)

I am deeply aware that Excellency Cáo has treated me generously, but I have received General Liú’s generous favour, and have sworn to die with him, and cannot turn my back on him. In the end I cannot stay, so I will establish a great service to repay Excellency Cáo and then go.

Guan Yu would get his chance to thank Cao Cao who entered a war with his old patron and northern rival Yuan Shao. In the opening exchanges of the war, Cao Cao went to relieve the defences at Boma and as part of the vanguard, Guan Yu spotted the brave and famed Yan Liang's standard. So he charged into Yan Liang's ranks, killed the commander and fought his way out. Yan Liang's army unsurprisingly collapsed and round one had gone to Cao Cao. In thanks, Cao Cao arranged for the Han court to ennoble Guan Yu and sent many gifts to Guan Yu but Guan Yu returned all the gifts, sent a letter and left to go to Liu Bei. Cao Cao ordered "That man has chosen his master. Let him go."

Guan Yu gave up a lot. He was guaranteed an income by being ennobled, he was valued and had earned the goodwill of arguably the most powerful warlord at the time but gave up the wealth, the most certain position and security. To go to a man who, in his revolt, had made an enemy of Cao Cao, had no base and would have to go from warlord to warlord for a time for aid, a far riskier and uncertain proposition. It made Guan Yu's reputation as an honourable man.

When Liu Bei, after three visits, hired the scholar Zhuge Liang as an adviser the two grew close to the point Liu Bei's old friends became unhappy and complained. Liu Bei firmly put his foot down, saying he needed Zhuge Liang like a fish needs water and this should not come up again. This rebuke seems to have settled things down.

In 211, Liu Bei would leave Guan Yu to manage his base in Jing province so Liu Bei could go into Yi province and eventually take it as part of Zhuge Liang's three-kingdom strategy. They would not be together again and when Liu Bei summoned reinforcements in 212, Zhang Fei would leave Jing. By 219, Liu Bei had seized Yi and the mountains of Hanzhong while parts of Jing remained under control, momentum was with them and they were the second power in the land. The symbolic seizure of Hanzhong meant Liu Bei declared himself a King and issued rewards, sending Fei Shi to give Guan Yu his rewards.

Guan Yu had spent nearly a decade in Jing, on the defensive and forced to cede terrority to Sun allies in 215 while Liu Bei gained new followers. Guan Yu seems to have become a tad insecure, he had to be reassured by Zhuge Liang (who played on his pride) that the famed new recruit Ma Chao was a hero comparable to Zhang Fei but not a match for the great bearded one, a letter Guan Yu would show around. When the rewards came out in 219, Guan Yu was furious at being ranked similar to Huang Zhong and Fei Shi soothed him, promising to return if Guan Yu was unhappy but he would feel bad for doing so and reminding Guan Yu that leaders had to reward new followers as well. But he also reassured Guan Yu that the special bond was not harmed (translation Rafe De Crespigny)

On this one occasion the King of Hanzhong is honouring the house of Han, and he rewards a man for his achievement, why should you believe that his affection for you is no different to that which he holds for others? You and his majesty are so close you might have a single body, you feel the same joys and the same sorrows, you share good fortune and ill. I do not believe you should judge his feelings by the highs and lows of official titles nor by the size of fiefs and gifts.

219 would be Shu-Han's peak. Guan Yu, having built up his strength in Jing, launched an attack on the Cao positions in Jing, if he took Fan and Xiangyang then the heart of Cao Cao's lands would be exposed. He captured the senior commander Yu Jin after floods wrecked the supporting army and Cao Ren the defender of Fan almost retreated but in the end, Guan Yu was driven off by reinforcements of Xu Huang. The problem would not be the defeat but what happened in Jing while Guan Yu was away would shatter Shu-Han's hopes.

Guan Yu had poured resources into the attack while confident that, with chief commander Lü Meng sick, his southern ally Sun Quan would not attack. Guan Yu had also clashed with his chief officers back guarding Jing in Mi Fang and Shi Ren over supply problems and had long not hidden his contempt for them. Sun Quan and Lü Meng saw Guan Yu personally as a threat, not helped by long-running tensions with Liu Bei and Guan Yu's less then diplomatic manner, as well as Liu Bei's forces being in Jing as a long-term threat so with Guan Yu distracted, they attacked. They seized the outposts on the river before they could send warning and then persuaded Mi Fang and Shi Ren to defect. When Guan Yu returned to Jing, the situation was hopeless, he was cut off from help and his army deserted on mass, Guan Yu would be captured and executed.

Zhang Fei had, bar the costing them a base in Xu back in 196, served Liu Bei well. A mighty and brave warrior, in 208 he led a rearguard of twenty cavalry against Cao Cao's pursuing forces, he broke bridges across a river and, defied the enemy cavalry to cross, challenging them to come die with him. They did not take up that kindly offer and it helped buy time. He had helped rescue the child heir Liu Shan from the kidnap attempt by Liu Bei's wife Lady Sun, he had taken part in the conquest of Yi including capturing Yan Yan and earning praise for releasing the defiant Yan Yan. When the experienced Cao general Zhang He led a raid into Yi, Zhang Fei was dispatched and using the mountain paths, was able to intercept and heavily defeat Zhang He who had only tens of men when he returned to Hanzhong.

In 221 when Liu Bei was organizing an army against Sun forces in Jing, disaster struck. Zhang Fei's history of violence against his subordinates had been a concern to Liu Bei who urged his brother to reign in the brutality, that the daily beating of his attendants might backfire. Finally, it did, Zhang Fei prepared to set out with 10,000 soldiers but two retainers Zheng Da and Fan Qiang assassinated him and then fled to the Sun lands. The camp commander sent word to Liu Bei and as soon as Liu Bei heard who the message was from, he knew Zhang Fei was dead.