Sima Lang, courtesy name Boda, was a man of Wen County in Henei Commandery. When he was nine, someone spoke his father's courtesy name in his presence, and Sima Lang said that one who slights another's parent does not respect his own, whereupon the guest apologized. At twelve he passed the examination on the classics and became a Boy Gentleman; when he was suspected of hiding his age because of his large build, he replied that both his mother's and his father's families had been big for generations and that reducing his age to win early advancement was not his intention, and the examiner thought him remarkable. Records, Wei 15 §15–16
Later, when troops rose east of the passes, the former Inspector of Ji Province Li Shao, who lived at Yewang, wanted to move to Wen County because Yewang was close to the rugged mountains. Sima Lang dissuaded him, saying that Wen and Yewang were as close as lips and teeth, so moving would only mean escaping ruin in the morning to await it in the evening, and that if someone the local people looked up to moved first, the counties along the mountains would be alarmed. Li Shao did not listen, and the people of the mountain areas did indeed fall into disorder, some moving inland and others turning to banditry and plunder. Records, Wei 15 §16
When Dong Zhuo moved the Son of Heaven to Chang'an and himself stayed at Luoyang, Sima Lang's father Sima Fang, the Secretary Censor, had to move west, so he had Sima Lang take the household back to their home county. Someone accused Sima Lang of planning to flee, and he was seized and brought before Dong Zhuo. When Dong Zhuo said that Sima Lang was the same age as his late son and yet had very nearly betrayed him badly, Sima Lang praised Dong Zhuo's virtue and achievements while lamenting that warfare was breaking out day after day and that the people were abandoning their homes and property to wander, and asked him to take past events as a mirror and reconsider. Dong Zhuo said that he too was aware of this and that there was sense in Sima Lang's words. Records, Wei 15 §17–18
Knowing that Dong Zhuo was bound to fall and fearing he would be detained, Sima Lang distributed his wealth in bribes to those who held power under Dong Zhuo and returned home. He told the elders of the district that Henei would become a battleground torn in four and split in five, and proposed that while the roads were still open the whole clan should go east to Liyang and rely on Zhao Weisun, an old in-law from their home district who commanded troops there as Internuncio Supervising the Camp. The elders, attached to their old homes, did not follow him; only Zhao Zi of the same county went with him, taking his household. Records, Wei 15 §19–20
A few months later the troops raised by the provinces and commanderies east of the passes, several hundred thousand strong, gathered at Xingyang and in Henei, but the commanders could not unite and let their troops plunder, so that nearly half the people died. Much later, after the eastern armies had dispersed and while Cao Cao was confronting Lü Bu at Puyang, Sima Lang brought his family back to Wen County. That year there was a great famine and people ate one another, but Sima Lang gathered in and cared for his clan and taught his younger brothers, not neglecting learning because the age was in decline. Records, Wei 15 §21
At twenty-two he was summoned by Cao Cao as a clerk on the staff of the Minister of Works and appointed Prefect of Chenggao, but left the post because of illness and then became Chief of Tangyang. His governance aimed at leniency and kindness and did not use the whip or the rod, yet the people did not break the prohibitions. He was so loved that when an order came for the county to build boats, people who had earlier been moved to the capital secretly returned to help. He was transferred to Prefect of Yuancheng and then entered the court as Registrar to the Chancellor. Records, Wei 15 §22
Sima Lang believed that the empire had collapsed like crumbling earth because Qin had abolished the system of the five ranks of nobility and the commanderies and kingdoms had no preparations such as hunts to train for battle. He proposed that even if the five ranks could not be restored, all provinces and commanderies should keep troops, guarding against the barbarians of the four quarters abroad and overawing lawbreakers at home. He also argued that since after the great disorder the land had no owners and had all become public fields, the well-field system should be restored at this time. These proposals were not put into effect, but the provinces and commanderies coming to command troops was what Sima Lang had originally intended. Records, Wei 15 §23–24
After he was transferred to Inspector of Yan Province, his governance and moral instruction prevailed widely and the people praised him; even on campaign he always wore coarse clothes and ate poor food, leading his subordinates by frugality. He was fond of judging character and of the classics, and when Li Di (李覿) of his home district and others gained great fame, he always openly belittled them; later, when Li Di and the others came to ruin, people of the time were impressed. When Zhong Yao and Wang Can wrote an essay arguing that no one but a sage could bring about great peace, Sima Lang held that men like Yi Yin and Yan Hui, though not sages, could bring about great peace if they succeeded one another for several generations. Records, Wei 15 §24–25
In the 22nd year of Jian'an (217) he joined Xiahou Dun, Zang Ba and others in a campaign against Wu. When they reached Juchao a great epidemic broke out among the soldiers; Sima Lang personally made the rounds and provided doctors and medicine, but he caught the illness and died, at the age of forty-seven. He left instructions that he be shrouded in ordinary clothes with a cloth robe and headscarf, and the people of the province remembered him with longing. When Emperor Ming came to the throne, his son Yi (司馬遺) was enfeoffed as Marquis of Changwu Village with a fief of 100 households. His younger brother Sima Fu had his own son Sima Wang made Sima Lang's heir, and when Yi died, Sima Wang's son Sima Hong succeeded. Records, Wei 15 §26
His figure also survives in other biographies. Cui Yan was on good terms with Sima Lang, and when Sima Yi had just come of age, Cui Yan told Sima Lang that his younger brother was probably beyond his reach, but Sima Lang did not think so. Yang Jun said that although the early reputation of Sima Lang's clan elder brother Sima Zhi did not match Sima Lang's, his real ability was in some respects superior. Wang Ling was a friend of Sima Lang and Jia Kui, and later, when he governed Yan and Yu Provinces, he carried on their reputation and achievements. Records, Wei 12 §16Records, Wei 23 §27Records, Wei 28 §5
In the assessment of this volume, Chen Shou wrote that since the end of the Han inspectors had overseen several commanderies, and that the men recorded here all had reputations that matched their reality, being well versed in the workings of affairs and displaying both authority and kindness. Records, Wei 15 §89