This monograph is a study of the Rgyal ba'i dben gnas rwa sgreng gi bshad pa nyi ma'i 'od zer (Rays of the Sun: A Statement about Rwa sgreng Monastery, Hermitage of the Victor), which is a newly discovered hand-written manuscript from the Fifth Dalai Lama's private library at 'Bras spungs monastery, Lhasa. It is the first known work devoted solely to Rwa sgreng monastery, the mother monastery of the Bka' gdams school founded by 'Brom ston Rgyal ba'i 'byung gnas (1005?1064) in 1057 after the death of his master Ati??a (982?1054). The Bka' gdams school no longer exists, but it has greatly influenced major schools of Tibetan Buddhism, such as Dge lugs, Bka' brgyud, and Sa skya school. Rwa sgreng monastery itself has shifted to the Dge lugs school, but it still has a strong presence as a monastery related to Bka' gdams school. Since this work was written at approximately the end of the thirteenth century, it is a relatively early text in the history of the Bka' gdams school, and it provides valuable historical, political, and sociological data on Rwa sgreng monastery. This study aids understanding of the history of Rwa sgreng monastery and the early Bka' gdams school?and more broadly illuminates important aspects of Tibetan history.