During the fourteenth century, with the rise of Dol po pa Shes rab rgyal mtshan (1292-1361), the gzhan stong philosophical tradition became a source of great controversy in Tibet. Dol po pa taught this new philosophical tradition for the first time to the wider Tibetan intellectual community. As Dol po pa's Jo nang teachings attracted an audience, many other philosophical giants of the day, such as Bu ston Rin chen grub (1290-1364), Red mda' ba Gzhon nu blo gros (1349-1412/13), and their students composed polemical works to refute Jo nang tradition. Lamp that Illuminates the Expanse of Reality was composed in the midst of this controversy to defend the Jo nang point of view. In it, its author, Gha rung pa Lha'i rgyal mtshan (1319-1402/03), attempts to prove that the Jo nang philosophical tradition is the definitive teaching and the quickest path to achieve the Buddhahood.