His paternal uncle Trimon, who had participated in the tripartite negotiations between Great Britain, China and Tibet in 1914, strongly encouraged him to take up an interest in Tibetan history.

Trimon in 1931, handed him many documents he had personally collected from the Simla Accord negotiations,[2] in order to counter the Chinese narrative accounts concerning his country.

The mission was aborted when the Tibetan cabinet minister in eastern Tibet, Ngapo Ngawang Jigme, apparently arranged an agreement with the Chinese.

[6] As events in Tibet deteriorated in the mid-fifties, he began to organize the Tibetan resistance together with the Dalai Lama's two older brothers, Gyalo Thondup and the Taktser Rinpoche also known as Thubten Jigme Norbu.

He died of stomach cancer in 1989, at the age of 82, in the home of his youngest son, Tsoltim Ngima Shakabpa, in Corpus Christi, Texas.

The historic document got lost from the Tibetan community in 1992 and there were rumours that it had been sold to antique dealers and reached into the hands of Chinese government officials.

[14] Issued by the Kashag to Tibet's finance minister Shakabpa for foreign travel, the passport was a single piece of pink paper, complete with photographs.

It has a message in hand-written Tibetan and typed English, similar to the message by the nominal issuing officers of today's passports, stating that "the bearer of this letter – Tsepon Shakabpa, Chief of the Finance Department of the Government of Tibet, is hereby sent to China, the United States of America, the United Kingdom and other countries to explore and review trade possibilities between these countries and Tibet.

The text and the photograph is sealed by a square stamp belonging to the Kashag and is dated "26th day of the 8th month of Fire-Pig year (Tibetan)" (10 October 1947 in the Gregorian calendar).