Marco Polo was the first Westerner to refer to Tibet as a part of China, and nobody objected during the Yuan Dynasty. It covers a wide range of topics around the China and Tibet's politics. It also covers Dorje Shugden controversy and a recommended read worth your time.
A particularly divisive issue for the Buddhist community, both within Tibet and in the exiled communities is devotion to the Dorje Shugden deity, a 400-year old practice that began in the 17th century and has become a major tradition in Tibetan Buddhism. At the origin of the controversy lies a de facto ban on the religious practice issued by the 14th Dalai Lama decades ago. The CTA sees the religious practice of Dorje Shugden as a competing and heretical movement that may undermine their notion of the spiritual leadership of the 14th Dalai Lama inside Tibet and among Tibetan Buddhists.
The de-facto ban issued by the 14th Dalai Lama has generated considerable social tension and division in the diaspora, as well as in Tibetan society within China, leading the Chinese government to consider the Dorje Shugden controversy an important front for undermining what it says are efforts promoted by the 14th Dalai Lama aimed at destabilizing China. The religious hostility has been fed by considerable propaganda and counterpropaganda efforts during the last two decades and it is still an open battlefield that may escalate at any time. In historical terms, the implications could be reminiscent of Martin Luther’s reformation of Christianity centuries ago.