Tritsuk Detsen (Tibetan: ཁྲི་གཙུག་ལྡེ་བཙན, Wylie: khri gtsug lde btshan), better known by his nickname Ralpachen (Tibetan: རལ་པ་ཅན, Wylie: ral pa chen) (c. 802 CE–838), was the 40th king of the Yarlung Dynasty of Tibet. He reigned after the death of his father, Sadnalegs, in c. 815, and grew the empire to its largest extent. He was murdered by his younger brother Langdarma in 838. Ralpachen is one of Tibet's three Dharma Kings, and referred to as "son of God" in the ancient Tibetan chronicle Testament of Ba.
Ralpachen was the second eldest of five brothers. The eldest, Prince Tsangma, took Tibetan Buddhist vows with the Nyingma school. The third, U Dumtsen known as Langdarma,is referred to in the sources as "unfit to reign". The younger two brothers both died young.
The Tibetan Empire, or the Empire of Tibet (Tibetan: བོད་ཆེན་པོ, Wylie: bod chen po, lit.'Great Tibet') was centered on the Tibetan Plateau and formed as a result of expansions under the Yarlung dynasty's 33rd king, Songtsen Gampo, in the 7th century. It expanded further under Trisong Detsen and reached its greatest extent under Ralpachen, stretching east to Chang'an, west beyond modern Afghanistan, south into modern India and the Bay of Bengal. It is referred to as Tufan or Tubo (吐蕃) in Chinese sources.
The Yarlung dynasty was founded in 127 BC in the Yarlung Valley along the Yarlung River, south of Lhasa. The Yarlung capital was moved in the 7th century from the Yungbulakang Palace to Lhasa by the 33rd ruler Songtsen Gampo, and into the Red Fort during the imperial period which continued to the 9th century. The beginning of the imperial period is marked in the reign of the 33rd ruler of the Yarlung dynasty, Songtsen Gampo. The power of Tibet's military empire gradually increased over a diverse terrain. During the reign of Trisong Detsen, the empire became more powerful and increased in size. At this time, a 783 treaty between the Tibetan Empire and the Tang dynasty defined the borders, as commemorated by the Shol Potala Pillar in Lhasa. Borders were again confirmed during the later reign of the 40th king Ralpachen through his 821–823 treaty, which was inscribed on a pillar at Jokhang. In the opening years of the 9th century, the Tibetan Empire controlled territories extending from the Tarim Basin to the Himalayas and Bengal, and from the Pamirs into what are now the Chinese provinces of Sichuan, Gansu and Yunnan. The murder of King Ralpachen in 838 by his brother Langdarma, and Langdarma's subsequent enthronement followed by his assassination in 842 marks the simultaneous beginning of the dissolution of the empire period.
The Yarlung dynasty (Tibetan: བོད་ཀྱི་གདོད་མའི་མངའ་མཛད།) was a Tibetan dynasty that existed from 127 BCE to 842 CE. It produced 42 rulers and gave rise to the Tibetan Empire period from 614 CE to 848 CE, credited to the 33rd monarch Songtsen Gampo, and lasting through to the 40th monarch Ralpachen. Ralpachen was murdered in 838 by his brother, the future 41st monarch Ü Dum Tsen, who in turn ruled for only one year (841–842) until his own murder. The dissolution of the empire occurred by 848.
The early Yarlung dynasty rulers lived before the Tibetan script was created, and their reigns and lives were documented through the lineage of verbal history until c. 650 when in the reign of the 33rd king of the Yarlung Dynasty Songtsen Gampo, the Tibetan alphabet and grammar were created and the royal record keeping of people and events called the Chronicle of Ba began. While some scholars feel unsure of the definitive existence due to the lack of written records before 650, the verbal lineage of Tibetan history is considered definitive for most scholars.
The Testament of Ba or the Chronicle of Ba(Tibetan དབའ་བཞེད or སྦ་བཞེད; Wylie transliteration: dba' bzhed or sba bzhed) is a Tibetan chronicle written in 8th century Classical Tibetan documenting the establishment of Tibetan Buddhism and the Vajrayana, Samye Monastery and the Samye Debate, and notable events and people in Tibet's history. Written during the Tibetan Empire period, it covers the reigns of kings Songsten Gampo, Trisong Detsen (r. 755–797/804), and the years after Rapalchen's reign. The monk Ba Salnang (Tibetan སྦ་གསལ་སྣང; Wylie transliteration: sba gsal snang) of the Ba Family was the main recorder of the Chronicle who used other scribes and members of the kings' courts.
In 2008, early versions of the text were said to have been discovered in London, where two manuscript fragments possibly dating to the 9th or 10th centuries are held by the British Library.
Trisong Detsen became one of Tibet's greatest kings during its empire era, and an unparalleled Buddhist benefactor to Guru Padmasambhava, to Khenpo Shantarakshita, to his court, and to the founding of the Vajrayana. By the end of his reign, he grew the extents of Tibet beyond their previous borders, reset the borders between Tibet and China in 783, and even occupied the capital of China at Chang'an, where he installed a king.
