The Tang unification had been far more prolonged and bloody than the Sui conquest. That the Tang regime lasted for nearly three centuries rather than three decades, as with the Sui, was largely the result of the system of government imposed on the conquered territories. The emperor Gaozu’s role in the Tang conquest was understated in the traditional histories compiled under his successor Taizong (Li Shimin; reigned 626–649), which portrayed Taizong as the prime mover in the establishment of the dynasty. Taizong certainly played a major role in the campaigns, but Gaozu was no figurehead. Not only did he direct the many complex military operations, but he also established the basic institutions of the Tang state, which proved practicable not only for a rapidly developing Chinese society but also for the first centralized states in societies as diverse as those of Japan, Korea, Vietnam, and the southwestern kingdom of Nanzhao.

The structure of the new central administration resembled that of Wendi’s time, with its ministries, boards, courts, and directorates. There was no radical change in the dominant group at court. Most of the highest ranks in the bureaucracy were filled by former Sui officials, many of whom had been the new emperor’s colleagues when he was governor in Taiyuan, or by descendants of officials of the Bei Zhou, Bei Qi, or Sui or of the royal houses of the northern and southern dynasties. The Tang were related by marriage to the Sui royal house, and a majority of the chief ministers were related by marriage to either the Tang or Sui imperial family. The emperor’s court was composed primarily of men of similar social origins. At that level the Tang in its early years, like the Sui before it, continued the pattern of predominantly aristocratic rule that had dominated the history of the northern courts.

Gaozu also continued the pattern of local administration established under the Sui and maintained the strict control exercised by the central government over provincial appointments. In the first years after the Tang conquest, many prefectures and counties were fragmented to provide offices for surrendered rebel leaders, surrendered Sui officials, and followers of the emperor. But these new local districts were gradually amalgamated and reduced in number, and by the 630s the pattern of local administration closely resembled that under the Sui. The merging of the local officials into the main bureaucracy, however, took time; ambitious men still looked upon local posts as “exile” from the main current of official promotion at the capital. Until well into the 8th century many local officials continued to serve for long terms, and the ideal of a regular circulation of officials prevailed only gradually.

Local government in early Tang times had a considerable degree of independence, but each prefecture was in direct contact with the central ministries. In the spheres of activity that the administration regarded as crucial—registration, land allocation, tax collection, conscription of men for the army and for corvée (unpaid labor) duty, and maintenance of law and order—prefects and county magistrates were expected to follow centrally codified law and procedure. They were, however, permitted to interpret the law to suit local conditions. Local influences remained strong in the prefectures and counties. Most of the personnel in these divisions were local men, many of them members of families of petty functionaries.

Fiscal and legal system

Gaozu had inherited a bankrupt state, and most of his measures were aimed at simple and cheap administration. His bureaucracy was small, at both the central and local levels. The expenses of government were largely met by land endowments attached to each office, the rents from which paid office expenses and salaries, by interest on funds of money allocated for similar purposes, and by services of taxpayers who performed many of the routine tasks of government as special duties, being exempted from tax in return.

Land distribution followed the equal-allocation system used under the northern dynasties and the Sui. Every taxable male was entitled to a grant of land—part of which was to be returned when he ceased to be a taxpayer at age 60 and part of which was hereditary. The disposal of landed property was hedged around with restrictive conditions. Great landed estates were limited to members of the imperial clan and powerful officials, various state institutions, and the Buddhist foundations. Although some land was hereditary, and more and more passed into the hereditary category with the passage of time, the lack of primogeniture meant that landholdings were fragmented among all the sons in each generation and thus tended to be small. It is unlikely that the system was ever enforced to the letter in any region, and it was probably never enforced at all in the south. But as a legal system governing registration of landed property and restricting its disposal, it remained in force until An Lushan’s rebellion in the 8th century.

The tax system based on this land allocation system was also much the same as that under the Sui and preceding dynasties. Every adult male annually paid a head tax in grain and cloth and was liable to 20 days of work for the central government (normally commuted into a payment in cloth) and to a further period of work for the local authorities. Revenues were collected exclusively from the rural population—the trade sector and the urban communities being exempt—and the system bore more heavily on the poor, since it ignored the taxpayer’s economic status.

The Sui had made a somewhat desultory attempt to provide China with a unified coinage. Gaozu set up mints and began the production of a good copper currency that remained standard throughout the Tang era. But cash was in short supply during most of the 7th century and had to be supplemented by standard-sized lengths of silk. Counterfeiting was rife, particularly in the Yangtze valley, where the southern dynasties had supported a more highly monetized economy and where the governments had exploited commerce as a source of revenue.

Gaozu also undertook a new codification of all centralized law, completed in 624. It comprised a code that embodied what were considered basic, unchanging normative rules, prescribing fixed penalties for defined offenses; statutes, comprising the general body of universally applicable administrative law; regulations, or codified legislation supplementary to the code and statutes; and ordinances, detailed procedural laws supplementing the statutes and issued by the departments of the central ministries. Under the early Tang this body of codified law was revised every 20 years or so. The systematic effort to maintain a universally applicable codification of law and administrative practice was essential to the uniform system of administration that the Tang succeeded in imposing throughout its diverse empire. The Tang code proved remarkably durable: it was still considered authoritative as late as the 14th century and was used as a model by the Ming. It was also adopted, with appropriate modifications, in Japan in the early 8th century and by the Koreans and the Vietnamese at a much later date.

Gaozu thus laid down, at the outset of the 7th century, institutions that survived until the mid-8th century. These provided strong central control, a high level of administrative standardization, and highly economical administration.