The Eighth and Ninth Dalai Lamas died prematurely in 1804 and 1815. Jamgon Kongtrul and Jamyang Khyentse Wangpo helped bring about what is known as the rime period, an era of tremendous ecumenical intellectual activity. The regency of Tsemonling Jampel Tsultrim Gyatso, born into the royal family of Chone (Amdo), lasted from 1819 until 1844. The Tenth Dalai Lama died in 1837 at the age of 22. From 1837 until 1865, the Nyarong War raged in Kham. Zhabkar Lama, the wandering yogi who was teacher to many later masters, was active throughout Tibet and as far as Nepal during the first half of the nineteenth century, passing away in 1851. In 1855, the Eleventh Dalai Lama died, and just two decades later in 1875, the Twelfth Dalai Lama died. The Thirteenth Dalai Lama was born in 1876, becoming head of state in 1895.