At the age of 50, he entered meditation retreat at Narthang. As he grew older, Karma Kagyu adherents, finding their sect was losing too many recruits to the monkhood to burgeoning Gelugpa monasteries, tried to contain Gelug expansion by launching military expeditions against them in the region. This led to decades of military and political power struggles between Tsangpa dynasty forces and others across central Tibet. In an attempt to ameliorate these clashes, from his retreat Gendun Drup issued a poem of advice to his followers advising restraint from responding to violence with more violence and to practice compassion and patience instead. The poem, entitled "Shar Gang Rima", "The Song of the Eastern Snow Mountains", became one of his most enduring popular literary works.