Lanna (English One Million Rice Fields, Thai: ล้านนา) was a kingdom in the north of Thailand around the city of Chiang Mai. It consisted of several partly independent city-states. It was also referred to sometimes as Lanna Thai.
The kingdom was founded in 1259 by King Mengrai the Great, when he succeeded his father as the leader of the Chiang Saen kingdom. In 1262 he founded the city Chiang Rai as his capital, naming it after himself. The kingdom quickly grew by unifying the many local Tai rulers of the area under his leadership, as well as by enlarging to the south by annexing the Mon kingdom of Haripunchai in 1292 - the area around the modern-day cities Lampang and Lamphun. In 1296 he founded the city of Chiang Mai as the new capital of the kingdom with help from allies Ngam Muang of Phayao and Ramkhamhaeng of Sukhothai.
The golden age of Lanna was in the 15th century. In 1477 the 8th of the Buddhist councils was held near Chiang Mai, which worked on improving the Buddhist scriptures. The previously independent city-state Nan, capital of a Tai Lue people, was added to the kingdom in 1449.
The decline of the kingdom started in the early 16th century, and became worse after the death of King Phraya Kaeo in 1526. There was fighting over who should succeed him. Some of the kings were assassinated; others had to abdicate. This political instability invited an invasion from the neighboring Burmese kingdom, and in 1558 Lanna had to surrender and thus became a vassal of Burma. When the dynasty of Mengrai became extinct in 1578, the Burmese sent their own princes to serve as rulers of Lanna.
The Siamese kings of Ayutthaya tried to capture Lanna several times, as the Burmese posed a threat to their kingdom as well. Even though around 1600 King Naresuan, and later in 1662 King Narai as well, succeeded in occupying Chiang Mai, they were repulsed by the Burmese after a short time.
In the early 1700s the Burmese divided the kingdom into a northern part, ruled from Chiang Saen, and a southern part, ruled from Chiang Mai. The northern part was for all practical purposes annexed by Burma, while the southern continued to be a vassal state.
After the Burmese destroyed Ayutthaya, King Taksin drove the Burmese out of Siam or Central Thailand. In the North, King Taksin helped Prince Kawila of Lampang to successfully drove out the Burmese. In the night of February 14, 1775 Chiang Mai fell to the Siamese. Prince Kawila became the first King of Lanna under Siamese rulership. King Rama I after ascending to the throne, awarded Kawila with more power, Kawila become the King of the Northern Kingdom who ruled 57 cities. The two monarchs has become more closed. Not only Princess Sri Anocha, King Kawila's sister, married to Crown Prince Boonma, King Rama I's only brother, but Princess Dararasmi, King Inthawichayanon's daughter also become King Rama V's Princess Consort. In 1877 a Viceroy from Bangkok was sending to help the King. In 1892 Lanna was formally annexed by Siam, and administrated as the Monthon Phayap. The last of the Lanna kings, Kaew Naovarat, never held any true administrative power. Upon his death in 1939, no successor was named to replace him.form wiki pedia