Marking Tibet’s peaceful liberation, the Agreement between the Central Government and the Local Government of Tibet, also known as the “17-Article Agreement” was signed in Beijing, May 23, 1951. [Photo/Tibet Geographic]

The 18th Army of the Chinese People's Liberation Army held a grand oath-taking ceremony in Leshan of Sichuan, March 7, 1950. [Photo/ Tibet Geographic]

The advance force group of the 18th Army arrived in Batang, August 2, 1950. Carrying various kinds of food in their hands, local Tibetans welcomed the advance force group on the bank of Jinshajiang River. [Photo/ Tibet Geographic]

Born in 1923, Robert Ford was the first foreign official in Tibet, who has worked in the Gaxag Government（the Tibet local government） in Lhasa since 1945. He was asked to train local rebel forces to use firearms in 1950. Captured after the Chamdo Campaign, he was sentenced to 10 years in jail in 1954 and was repatriated to England one year later. [Photo/ Tibet Geographic]

After the Chamdo Campaign, Wang Qimei(M), director of People's Liberation Committee in Chamdo, met with Ngapoi Ngawang Jigmei(L) in former office of Kalon . [Photo/ Tibet Geographic]

Soldiers of the 18th Army are climbing over the Gyamda Mountain and marching towards Lhasa. [Photo/ Tibet Geographic]

Soldiers of the 18th Army are climbing over the Niba Mountain and marching towards Gyamda. [Photo/ Tibet Geographic]

The day after the “17-Article Agreement” was signed, Chairman Mao Zedong（R）met with the Tibet Delegation and hosted a banquet in Zhongnanhai, headquarters of China’s Central Government in Beijing. The photo shows Chairman Mao Zedong(R) is talking with Ngapoi Ngawang Jigmei(L). [Photo/ Tibet Geographic]

The whole 18th Army is very excited at the signing of the 17-Article Agreement, May 23, 1951. [Photo/ Tibet Geographic]