Tibetan seals include both the seal stamps [which could also be referred to by the Slavic term "petschaft") and the associated seal impressions. Seal impressions were used as a means of authenticating Tibetan documents and as an equivalent to the signature at the end of a letter, which is common in the Western world. The use of imprints on sealing wax to seal letters is also documented.
The history of the use of seals in Tibet has not yet been researched. The early use of seals at the time of the Yarlung Dynasty [7th - 9th century AD] has been documented.
Use of Tibetan seals
The oldest known seal impressions are found on Tibetan documents found in various places in Chinese Turkestan [now Xinjiang], notably those from a Buddhist cave temple at Dunhuang. These documents date mainly from the late 8th to mid-9 centuries, when large parts of Chinese Turkestan were occupied by Tibet. As the vast majority of the Tibetan population were illiterate, seals were used instead of signatures.
The first Tibetan scholars to decipher official Tibetan seals were the German missionary and Tibetan scholar A. H. Francke and the Englishmen Walsh and Wadell. Their attempts at decipherment were based on an earlier publication by Sarat Chandra Das, which dealt with various Tibetan scripts, including the Phagspa script often used on official seals. The Reverend G. Tharchin published a book on official Tibetan seals in 1956. The German Tibetologista Dieter Schuh succeeded in systematically researching and completely reading the often trilingual [Tibetan, Chinese and Manchu] official seals. This was followed by works on official seals by Tibetan and Chinese scholars. By contrast, the many private seals and those used in monasteries and subordinate government offices have remained largely unexplored and unpublished.
The oldest known seal impressions are found on Tibetan documents found in various places in Chinese Turkestan [now Xinjiang], notably those from a Buddhist cave temple at Dunhuang. These documents date mainly from the late 8th to mid-th centuries, when large parts of Chinese Turkestan were occupied by Tibet. As the vast majority of the Tibetan population were illiterate, seals were used instead of signatures.
Since the time of the Yuan Dynasty, Chinese emperors have awarded seals to numerous Tibetan potentates, usually made of precious materials such as gold, silver, jade or ivory. The seals awarded to Panchen Lamas, Dalai Lamas and regents are particularly impressive for their size and the artistic design of the inscriptions.
Monastery and private seals
Monastic and private seals were also used to seal documents such as contracts of sale or donation. Private seals are usually made of iron or embossed silver sheet, forming a cylinder in which a round iron plate with the seal's inscription is embedded. Monastic seals are usually more elaborate. They may have a finely carved wooden or ivory handle into which a square iron plate is inserted, or they may be made entirely of metal, the handle often being intricately forged with openwork ornamentation. The use of iron to make seals is a Tibetan peculiarity that could only develop because of the dry highland climate, which causes little corrosion.
Official seals issued by China are often trilingual: Tibetan, Chinese and Manchu. Private and monastic seals generally use only Tibetan, although the script varies. On monastic seals, which are usually square, the square script developed by Phagspa in the 13th century, also known as Phagspa script after its inventor, is most common. There are also ornate scripts such as Lantsa [Ranjana].
The Tibetan dbu-can script, which often abbreviates the name of the seal's owner, is usually found on the mostly round, sometimes square private seals. Some private seals have no inscription and instead show a lucky symbol, often one of the eight Buddhist symbols [Ashtamangala]. Round private seals usually show a sun and moon symbol or three dots around the edge. The latter probably represent the Buddhist symbol Triratna, which means Buddha, Sangha [the monastic community] and Dharma [the teaching].
These symbols indicate to the uninitiated which is the upper part of the seal, thus preventing the seal impression from appearing upside down. The seals were imprinted on the document with red [only on the seals of the highest dignitaries such as the Dalai Lamas and Panchen Lamas] or black ink. Sealing wax was only occasionally used to seal documents for dispatch, but not to give authority to the document. The frequent use of these substances in the Western style only became fashionable after 1900, following the establishment of the Tibetan postal system, when letters were sealed with sealing wax and the wax was imprinted with a private seal. Seal impressions in clay, as found in Tibet's southern neighbours India and Nepal, are not known from Tibet.
Source: Translation from German Wikipedia