well Aeneas or any other chinese memeber...correct me if i am wrong...wasn't mainland china, which was originally integrated with tibet(which was never a separate entity originally)seperated from tibet by the british?
i have heard that the british were responisble for that...because though the british dint conquer china but had a very strong political presence in china.
British had done so much in Asia,such as,conquer hundreds of kingdoms in subcontinent,and united into now India country.they want to conquer more land,including Tibet.But you know,China are always being a big empire from thousands years ago.and when British came to Tibet,they meet a empire,though weak,but still a empire.which had ruled Tibet for at least 200 years.
there had been some struggle between British and China and maybe Russia in Tibet.Fortunately China didn't lost Tibit at last.and then WWWI and WWWII broken out.British turn their focus to Europe.
things going on until mao became the leader of China,of course you know he is a powerful leader,PLA go to Tibet and ending all the unsteadiness of Tibet.then Tibet under the control of Beijing again firmly.
Tibet had never be an independent country in those years,but some thing like a land of warlord,under the central government of China,though the control were weak,like the rest part of China.
Even dalai lama can't rule all earth of Tibet,he is just the biggest landlord and the religious leader of Tibet.there are many chiefs in Tibet at that time,they fight each other for land,for slaves,or for hate.
And British really leave a problem to China and India---the border issue.Of course we know,there had been no legal border between China and India,because we didn't know the concept until British came.so the only way to decide it is look up for history.and we two country show history proof which in favor of each.
I'm sorry,I guess my English need more exercise.