Chiang Rai was officially re-founded in 1844, with vassalage status under Bangkok. City rulers presented themselves in Bangkok with tribute of gold and silver trees, every 3 years. Between 1850 and 1854, Chiang Rung (Cheli, Xishuangbanna) sent tribute to Bangkok, requesting Siamese assistance against Burmese aggression. King Mongut (Rama IV) sent Lanna troops against Keng Tung, but they failed. The Chiang Rung section of Lanna was then assimilated into China.

Daily life under local princes, after the great depletions of two centuries of warfare, was returning to the style it had maintained in earlier centuries, when the British and French began to arrive in force. In 1829, Chiang Mai received its first influx of European foreigners, but Bangkok only took measures to assert firmer control in the 1880s. As the Europeans began harvesting hundreds of square kilometers of teak, settlers began to arrive from the central plains. The teak business needed Karen mahouts, and due to the low population density (from war and disease) other tribal peoples from further north began to move in. Government officials began to come too, with instructions to revitalize the cities of Chiang Rai and Chiang Saen.

Trade with China and the Shan States dominated Lanna markets for most of the 19th century. By the 1890s, the Ping was being dredged regularly, and river traffic could bring business to and from Uttaradit. There were also traders from Tak and Chiang Mai, who were often Chinese emigrants. Trade was growing, and with it, influence from Bangkok.

In 1455, customs of Tai principalities became clarified in Ayudhayan law. Details of the complex hierarchical structure and position of each person were carefully specified under King Trailokanat (1448-1488). The aristocracy was numerically delineated, and the feudal structure became a clear calculation of precisely who was responsible to whom (everyone in society was responsible to someone, usually just one person), in a detailed taxation system. Law now assigned everyone a number of units of Sakdi Na ('field power'). Well before the 15th century, this had symbolized actual measured rice fields. Monks, housewives, slaves, and Chinese merchants were all assigned Sakdi Na numbers. Peasant freemen had Sakdi Na of 25, slaves 5, government service craftsmen 50, and petty officials 50 to 400. Bureaucratic nobility, from heads of minor departments with Na 400, up to the highest ministers of state, with 10,000 was below upper levels, which ranked equal to junior members of the royal family. At Na 1000, a person's title graduated from Nai to Jao (prince). Governors of the city-states were Jao Moon, Prince of ten thousand. The heir apparent ranked 100,000. The law ranked all conceived positions, designating everyone's comparative position.

Sakdi Na status was relevant to civil and criminal law, with fines and punishments proportional to status. A peasant assaulting a powerful official was a more serious matter than assault on a slave, as the matter went even to the king, from whom the assaulted official derived status. Both the amounts of fines determined by courts, and of compensation paid for murder, were determined by Sakdi Na grades. Through this law, royal authority regulated human inequalities, to maintain order. Under this system, subsistence villagers had to work harder, and produce greater surplus to supply to the state.

When Lanna became part of Siam, it inherited the Sakdi Na system. The hierarchic structure of Lanna, however, remained quite much less formal or rigid than that of the Chao Praya basin. Social mobility was always more likely and accepted.

The founder of the Chakri Dynasty, Rama I (Chaophraya Chakri, Kawila's co-commander), enlarged Siam to its greatest extent. Almost twice Thailand's present size, it was better regarded as an empire, as there were subordinate kings and rulers, particularly in the Shan States, Laos, Cambodia and some northern Malay city-states (parts now lost). Rama I accepted tribute from Lanna, but had no strong influence over internal politics, or control over traditional alliances. No permanent officials were put in place, but Kavila's sister, Sri Anocha, married the brother of Rama I. In 1799 Kavila was whipped 100 strokes for refusing to report to that king in Bangkok...

By the reign of Rama III (1824 - 51), the appointment of Lanna princes and senior officials was subject to Bangkok royal approval. From misapprehension of the Anglo-Burmese War of 1824-25, Vientiane set out to attack Bangkok and took Korat, but in early May, 1827, the Siamese met the Lao army at Nong Bua Lamphu, 50 miles south of Vientiane, and triumphed. The Vientiane king fled to Vietnam while the Siamese looted his capital and destroyed its defenses, then subjugated the region, taking prisoners for relocation. In August, 1828, with Vietnamese help, Laos recaptured Vientiane, but Rama III again sent troops who prevailed. The Vientiane king, Anu, died in Bangkok, humiliated by being put on public display. Prisoners were also brought south, to central plains towns around the mouth of the Chao Phraya, and to the Khorat Plateau. 40 years later French explorers found only forest and ruins at Vientiane. Central Laos was repeatedly raided in the 1830s and 40s for more relocates. Black Tai leaders resumed allegiance to Siam, paying tribute through Luang Prabang. The Siamese organized new Muang at Nong Khai, Nakhon Phanom and Sakhon Nakhon with people from the east side of the Mekong, which was left under-populated even until now.

Rama IV (King Mongut, 1851 - 68) managed his vassal royalty more gently, giving presents of fancy textiles and regalia intended as symbols of office, when he received tribute. Lanna princes were still chosen by senior Lanna royalty and their ruling councils, subject only to the Chakri king's approval. Western powers were demanding end to restrictions on trade, direct diplomatic relations, and consular legal jurisdiction over their nationals. Siam was at its largest, dwarfing its neighbors. Mongut inherited a war as Chiang Rung, in Yunnan, had requested protection against Burma. In 1852-3 and again in 1854, Mongut sent Lanna forces against Keng Tung, but they failed. The second Anglo-Burmese War of 1852 changed the outlook. Siam opened to foreign trade, and within 10 years Bangkok's sea trade had doubled, much from export of rice. Ministries were less restrained by royal authority than they had been under Rama I, though, and control over personnel remained the main political power (and quite important economically too). Resettlement programs were thus a prominent feature of the day.

Rama V (King Chulalongkorn), fearing British and French colonial ambitions, decreed all new princes to be directly appointed by the royal throne in Bangkok. In 1883, though, he wrote to his High Commissioner in Chiang Mai that Chiang Mai was a vassal state (prathetsarat), not part of Siam, and that he didn't want to destroy the ruling families or upset their status. He wished to wield power with "brains and intelligence more than power and force."

In order to combat the colonialist ambitions of Europeans, though, the Chakris found need of Western-style history, and a nationalistic myth was constructed. The method France used to take Laos was to claim it as a dependency of Vietnam. Laos had paid tribute to the Vietnamese; the French, upon taking Vietnam, claimed also its supposed vassal. But among the Tai, 'tribute' was regularly paid to many places. The Chakri kings felt a clear, pressing need to make clear what was theirs, and why. The history produced to resist the Europeans, though, is of little use today. Another important example of the need of such skillful craft to deal with Europeans involves the teak trade.