In 1900, the British officer, Youngshusband crossed the Himalayas and occupied Tibet. It was the same time that Hong Kong was secured as a base for Opium distribution. This is the time when Tibet's independence movement started. China was too weak at the time to challenge the British.
Hitler sent an SS expedition to Tibet to learn more about Lamaism. He became intrigued when he read the superior race ideas presented in the Shambala myth in the Kalachakra Tantra. He usurped the Swastika from one of their good luck symbols.
After Mao Tse Tung liberated China from the Kou Ming Tung, they moved into Tibet. Unlike the movie depiction, there was no fighting when they marched into Lhasa. They built roads, hospitals and schools but otherwise made little change in Tibet's feudal system.
This was the time when the CIA made contact with the Dalai Lama and put him on a yearly stipend. The purpose of this was to foment unrest. ["CIA bankrolled Tibetan independence movement" AP]
The Dalai Lama claims in his autobiography that it was his brother that was responsible for the mayhem. It is true that his brother had a stronger connection to the CIA but the check was cut out to DL. DL's complicity is also detailed in the book "The Struggle for Modern Tibet: The Autobiography of Tashi Tsering", one of DL's boy dancers who struggled for Tibetan independence.
In 1959 the Chinese moved to make changes in the feudal kingdom of Tibet. As they did in all of their outlying provinces, they freed the slaves and offered free school and health care for the entire population. They forced DL to give up his slaves. DL as leader of the Lamaist class led a failed revolt that led to his departure from Tibet. And while the Dalai Lama says he will no longer own slaves and he will no longer claim his royal rights over the serfs of Tibet, it's only because the Tibetan workers and peasants have won their freedom and won't let the oppressive conditions return. DL also claims in his biography that he no longer believes that violence should be used to advance his goals. This claim is made because he allowed his monks to be trained as mercenaries to cause havoc in Tibet. ["The CIA's secret war in Tibet" Chicago Tribune]
His brother is in the US now and runs a covert organization, the Free Tibet Committee, that ensnares those that are concerned for human rights.