information:filtering, structural:summarization
Late Kaihuang era

In 590, apparently jealous of the talent of the official Li Delin, who had been key in his takeover of power as regent and who had contributed to the strategies in conquering Chen, Emperor Wen, believing in several false accusations against Li, removed Li from his office and made him a provincial governor. Li would not return to the central government for the rest of his life.

After Chen was conquered, Sui began to apply its laws over Chen's former territory—which brought resentment from the gentry, as they had been treated preferentially under Chen and its predecessor dynasties in the south. Su Wei further wrote a work known as the Five Teachings (五教, Wu Jiao) which is no longer extant but thought to be a work about loyalty to Sui and ordered that all former Chen subjects read and memorize it, leading to further resentment. When a rumor spread that Sui would move Chen subjects into the Guanzhong region in 590, nearly all of former Chen realm rose in rebellion, but in an unorganized manner. Emperor Wen sent Yang Su to quell the rebellions, and the rebels were no match for Yang Su; within the year, the rebellions were put down.

In 591, Tuyuhun sought peace and, as per custom, its khan Murong Shifu (慕容世伏) offered his daughter to be a concubine for Emperor Wen. Emperor Wen accepted the peace offer but declined the offer of Murong Shifu's daughter. (It was, however, around this time that he did take Chen Shubao's sister and another woman from Jiankang, Consort Cai, as concubines, although it appeared likely that Consort Cai was never able to have sexual relations with Emperor Wen while Empress Dugu was alive; Consort Chen, as the sister of a submissive former sovereign, might have had sexual relations with Emperor Wen on an infrequent basis, but it is not clear.)

In spring 592, the official He Tuo (何妥), who, despite his senior status over Su Wei's son Su Kui (蘇夔), was losing out against Su Kui over a debate as to the designation of official music styles for Sui. In anger, He Tuo accused Su Wei of factionalism, and after investigation by Emperor Wen's son Yang Xiu and the official Yu Qingze (ted zhang), Su Wei was removed from office. After Su Wei's removal, Yang Su and Gao Jiong became effectively the co-prime ministers. When Heruo Bi, who believed that he should have been prime minister, complained, Emperor Wen removed him from his post as well and stripped him of his ducal title, but restored the ducal title a year later. (Su Wei, however, was back in his post at the latest by 595.)

Also in 592, Emperor Wen, reacting to an overflowing abundance of food and silk in the governmental stores, reduced the taxes heavily, and he also sent messengers around central China, redistributing land to give the poor farming land.

In 593, Emperor Wen commissioned a summer vacation palace, Renshou Palace (仁壽宮, in modern Linyou County, Shaanxi), away from Chang'an, with Yang Su in charge of the project. The palace was far more luxurious than Emperor Wen expected, and its construction cost many lives. (When it was completed in spring 595 and Emperor Wen visited the palace, he was initially very displeased with Yang Su, but Empress Dugu persuaded him that Yang Su knew that he had little other entertainment, and she awarded Yang Su much treasure to show appreciation.)

Also in 593, knowing that the Princess Dayi was still resentful of him, Emperor Wen had the official Pei Ju inform the cousin and subordinate khan to the Göktürks' Dulan Khan, Ashina Yongyulü, the Tuli Khan Ashina Rangan (son of Ashina Chuluohou) that he would let Ashina Rangan marry a Sui princess if Ashina Rangan was able to get Princess Dayi killed. Ashina Rangan, in response, accused Princess Dayi of adultery, and Ashina Yongyulü killed her and requested another marriage with Sui. Instead, Emperor Wen agreed to marry a princess to Ashina Rangan, in order to create greater friction between them.

In 594, in response to another famine in the Guanzhong region, Emperor Wen again temporarily took up residence in Luoyang. He also, to share in some of his people's suffering, abstained from meat for a year.

Late in 594, Yang Guang submitted a petition that Emperor Wen carry out the ancient ceremonies of worshipping the heaven and earth gods at Mount Tai. Emperor Wen declined to carry out a full set of ceremonies due to its costs, but in spring 595 carried out an abbreviated version to seek blessings from the gods due to the ongoing drought.

Also in spring 595, Emperor Wen ordered that no weapons be held by private individuals and that all of them be collected and destroyed, although he exempted the border provinces from this edict.

In 596, Emperor Wen created a daughter of a clansman the Princess Guanghua and married her to Murong Shifu, to cement the peaceful relations with Tuyuhun.

In 597, Cuan Wan (爨翫), the chief of the Nanning Tribe (南寧夷, located in modern Qujing, Yunnan), rebelled. Emperor Wen sent the general Shi Wansui (史萬歲) the Duke of Taiping against Cuan, forcing him to surrender. Initially, Shi was to take Cuan to Chang'an to be presented to Emperor Wen, but Cuan bribed Shi, and so Shi allowed him to stay. Also in 597, Li Guangshi (李光仕), the chief of the aborigine people in Gui Province (桂州, roughly modern Guilin, Guangxi), also rebelled. Emperor Wen sent the generals Wang Shiji (王世積) and Zhou Fashang (周法尚) against Li, and Zhou was able to defeat and kill Li. However, in the fall, Li Shixian (李世賢), who might have been related to Li Guangshi, rebelled at Gui Province, and Emperor Wen sent Yu Qingze the Duke of Lu to attack Li Shixian; Yu was successful in suppressing the rebellion. Subsequently, however, Yu's brother-in-law Zhao Shizhu (趙什住), who had an affair with Yu's concubine, falsely accused Yu of treason, and around the new year 598, Yu was executed.

Also in 597, Emperor Wen felt that the punishment for official misconduct was too light, and authorized that supervising officials would be permitted to batter their subordinates with large canes if they felt that the legally prescribed punishment was too light in comparison to the degree of misconduct. Further, also believing that there was too much theft and robbery throughout the realm, he increased the punishment for theft to death—a law that he subsequently abolished.

Also in 597, Emperor Wen's son Yang Jun the Prince of Qin, the commandant at Bing Province (并州, roughly Taiyuan, Shanxi), was poisoned, but not to death, by his jealous wife Princess Cui. After Yang Jun was taken back to Chang'an for treatment, Emperor Wen discovered that Yang Jun had been wasteful at his post, and removed him from all of his offices, allowing him to only retain the title of imperial prince. When Princess Cui's poisoning was discovered, Emperor Wen ordered Yang Jun to divorce her, and subsequently ordered her to commit suicide. When Liu Sheng (劉昇) and Yang Su suggested that the punishment against Yang Jun was overly severe, Emperor Wen responded to Yang Su:

Also in 597, Ashina Rangan arrived at Chang'an, and Emperor Wen gave him the daughter of a clansman, whom he created the Princess Anyi, to be his wife, and awarded Ashina Rangan with much treasure, to try to break the bond between him and Ashina Yongyulü. From this point on, whenever Ashina Yongyulü would prepare to attack, Ashina Rangan would report his plans to Emperor Wen, allowing Sui forces to become prepared.

In 598, King Yeongyang of Goguryeo attacked Ying Province, and while the governor of Ying Province, Wei Chong (韋沖), fought off the Goguryeo attack, Emperor Wen was angered. He sent his son Yang Liang the Prince of Han and Wang Shiji to serve as commanding generals, with Gao Jiong serving as Yang Liang's assistant, and the former Chen general Zhou Luohou (周羅睺) serving as the commander of the navy, to attack Goguryeo. However, the forces ran into food supply problems, and the ships ran into a storm and suffered great losses. Both at sea and on the ground, Goguryeo forces inflicted heavy losses on the Sui forces. Nevertheless, King Yeongyang ceased his raids into China and so Emperor Wen called off the campaign against Goguryeo, unable to commit yet another enormous force to punish Goguryeo after the recent losses. As King Wideok of Baekje offered assistance to Sui during the campaign, this precipitated a conflict between Goguryeo and Baekje.

Also in 598, Cuan Wan rebelled again, and Yang Xiu accused Shi of accepting bribes from Cuan earlier. Emperor Wen considered executing Shi, but ultimately chose only to remove him from his posts, and it appeared soon after Shi was restored to his post.

In 599, after Ashina Rangan reported that Ashina Yongyulü was planning to attack, Emperor Wen took preemptive action and had Gao Jiong, Yang Su, and Yan Rong (燕榮) command a three-pronged attack against Ashina Yongyulü, with Yang Liang in nominal command but not at the frontline. In response, Ashina Yongyulü and Ashina Dianjue made a joint attack against Ashina Rangan, defeating him and largely seizing his tribe. Ashina Rangan fled to Sui, and Emperor Wen treated him as an honored guest. Subsequently, both Gao Jiong and Yang Su engaged Göktürk forces and repelled them.

Also in 599, with Wang Shiji's subordinate Huangfu Xiaoxie (皇甫孝諧) accusing Wang of treason after Wang refused to shield Huangfu after he committed crimes, Emperor Wen believed Huangfu and executed Wang.

By this point, Yang Yong the Crown Prince had lost the favor of both Emperor Wen and Empress Dugu, over his being overly wasteful (which displeased Emperor Wen) and having many concubines (which displeased Empress Dugu). They therefore considered deposing him and replacing him with Yang Guang. When Empress Dugu hinted as such, Gao Jiong stated clear opposition. Meanwhile, Emperor Wen himself had engaged in sexual relations with Yuchi Jiong's granddaughter, who had been made a servant after her grandfather's defeat—and when Empress Dugu found out, she had Yuchi Jiong's granddaughter killed. Emperor Wen was exceedingly angry and rode away from the palace on a horse, returning to the palace only at the urging of Gao and Yang Su—but with Gao further angering Empress Dugu when Gao referred to her as "a woman." In 599, Gao was accused of associating with Wang Shiji and removed from his posts. Subsequently, Gao was accused of cursing Emperor Wen, but when the sentence of death was recommended, Emperor Wen commented that he could not kill Gao soon after killing Yu and Wang, and therefore only reduced Gao to commoner rank.

In winter 599, Emperor Wen created Ashina Rangan Qimin Khan, and commissioned Zhangsun Sheng to build the city of Dali (大利, in modern Hohhot) to house Ashian Rangan's people, and also sent an army to protect Ashina Rangan. By now, the Princess Anyi had died, and Emperor Wen married another daughter of a clansman, whom he created the Princess Yicheng (義成公主), to marry Ashina Rangan. Soon thereafter, Ashina Yongyulü was assassinated, and Ashina Dianjue declared himself Bujia Khan. In summer 600, Ashina Dianjue attacked Ashina Rangan, and Sui forces fought off Ashina Dianjue's attack, further causing Ashina Rangan to be grateful to Sui.

In fall 600, with Yang Guang and Yang Su forming a faction, with tacit support of Empress Dugu, they had Yang Yong's associate Ji Wei (姬威) falsely accuse Yang Yong of plotting treason. Emperor Wen deposed Yang Yong and replaced him with Yang Guang. Emperor Wen also put a number of officials whom he believed to be part of Yang Yong's faction, including Shi and Yuan Min (元旻) the Duke of Wuyuan, to death.