Tibetan history can be traced thousands of years back. However, the written
history only dates back to the 7th century when Songtsan Gampo, the 33rd Tibetan
king, sent his minister Sambhota to India to study Sanskrit who on his return
invented the present Tibetan script based on Sanskrit.
Tibet's history can be divided into four periods:
1. The Tsanpo's Period
This period starts from Nyatri Tsanpo, the first of the Tsanpos, in 127 B.C
(historians differ in view of the date, but this date is taken from the White
Annales, a reliable book on Tibetan history) and ends in 842 A.D. at the death
of Lang Dharma, the last of the Tsanpos, who was assassinated by a Buddhist monk
owing to Lang Dharma's ruthless persecution of Buddhism. During this period some
42 Tsanpos had ruled over Tibet among which Songtsan Gampo's rule was considered
as the zenith. Songtsan Gamoi was an outstanding ruler, he unified Tibet,
changed his capital to Lhasa, sent Sambhota to India to study Sanskrit and
promulgated a script for the Tibetan on the latter's arrival to Tibet, married
Princess Wencheng of the tang Court and Princess Bhrikuti Debi of Nepal, built
the Potala and the temple and the temple of Jokhang
2. The period of Decentralization
This period began in 842 A.D. the year of Lang Dharma's assassination, and
ended in about 1260 A.D, when Pagpa, the Abbot of Sakya monastery, became a
vassal of Kublai Khan, the first Emperor of the Yuan Dynasty. During this period
a little is known in history except that Tibet became decentralized into a
number of petty principalities.
3. The period of Sakya, Pagdu, and Karmapa's Rule
This period began with Sakya's rule over Tibet, followed first by Pagdu's
rule in Lhaoka and then by Karmara's rule in the Tsang region (Shigatse). The
sakya period was the time written Tibet officially became an inseparable part of
China.
This period lasted from 1260 A.D to 1642 A.D during which political
powers centered in the three regions of Sakya, Pagdu, and tsang successively
ruled over Tibet.
4. The period of the gandan Podrang's Administration
This period is the period in which the Dalai Lama ruled Tibet. It started
in 1642 A.D. when the 5th Dalai Lama overtook the ruling power from the Tsang
ruler. It basically ended in 1951 when Tibet was liberated and came to a
complete end in 1959 when rebellion led by the Dalai Lama was pacified and the
People's Government of the Tibet, Autonomous Region was set up.
(Source: China Daily)