 Tsongkhapa wrote his major works on tantra and ethics at the same time as his major philosophical works. Volumes 3–12 of his collected works in 18 or 19 volumes deal exclusively with topics based on tantric sources. In 1405 he completed his Great Exposition of Tantra (sNgags rim chen mo) (Hopkins 1980, Yarnall 2013) a companion volume to his Great Exposition, where, in harmony with his philosophy, he argued that tantra is defined neither by special insight (Sk. vipaśyana) or Mahāyāna altruism (Sk. bodhicitta), but solely by deity yoga (Tib. lha'i rnal 'byor) (Hopkins 1980).