Sönam Rapten (bsod nams rab brtan; 1595–1658), initially known as Gyalé Chödze and later on as Sönam Chöpel, was born in the Tholung valley in the Central Tibetan province of Ü. He started off as a monk-administrator (las sne, lené) of the Ganden Phodrang, the early Dalai Lamas' residence at Drepung Monastery, outside Lhasa, Tibet. From around or before the age of 20 he became the Treasurer and the "Chagdzo" (phyag mdzod - the personal manager and principal attendant) of the Fourth (1589-1617) and, subsequently, the Fifth Dalai Lama (1617-1682). He presided as the most senior official of the Gelugpa school of Tibetan Buddhism for over 40 years (circa 1615–1658).
The Gelugpa school was twice threatened with extinction in the first half of his tenure, in 1618 and again in 1634. Despite this, under Sonam Rapten's leadership, and thanks to both Mongol military assistance and the pre-eminence of his Ruler the Fifth Dalai Lama as a spiritual leader, the Gelugpa rose to govern most of Greater Tibet by the time he reached 47 years old (1642). Subject to intermittent interference from neighbouring countries, the government he helped to found continued to rule at least the main area of Central Tibet for over 300 years.
