Sikkim had a long history of relations with Tibet. Buddhism was the religion and the Chogyal rulers descended from Shabdrung Ngawang Namgyal, a Tibetan saint who unified Bhutan. In the first half of the 19th century, the British extended their influence to the Himalayas and Sikkim signed an agreement with the British in 1861. As the British established relations with Nepal, Sikkim and Bhutan, Tibetan influence wanned and in Lhasa and Beijing it was feared that if left unopposed, the British would encroach into Tibet through Sikkim.