Lojong (, 'mind training') is a contemplative practice in the Tibetan Buddhist tradition which makes use of various lists of aphorisms or slogans which are used for contemplative practice. The practice involves refining and purifying one's motivations and attitudes. There are various sets of lojong aphorisms; the most widespread text in the Sarma traditions is that of Chekawa Yeshe Dorje (12th century). There is also another set of eight lojong slogans by Langri Tangpa. In the Nyingma tradition, there is a list of seven lojong slogans which are part of the Dzogchen Nyingthig lineage. Lojong slogans are designed as a set of antidotes to undesired mental habits that cause suffering. They contain both methods to expand one's viewpoint towards absolute or ultimate bodhicitta, such as "Find the consciousness you had before you were born" and "Treat everything you perceive as a dream", and methods for relating to the world in a more constructive way with relative bodhicitta, such as "Be grateful to everyone" and "When everything goes wrong, treat disaster as a way to wake up." Prominent teachers who have popularized this practice in the West include Pema Chödrön, Ken McLeod, B. Alan Wallace, Chögyam Trungpa, Sogyal Rinpoche, Kelsang Gyatso, Norman Fischer and the 14th Dalai Lama. Lojong mind training practice was developed over a 300-year period between 900 and 1200 CE, as part of the Mahāyāna school of Buddhism. Atiśa (982–1054 CE), a Bengali meditation master, is generally regarded as the originator of the practice. It is described in his book Lamp on the Path to Enlightenment (Bodhipathapradīpaṃ). The practice is based upon his studies with the Sumatran teacher, Dharmakīrtiśrī (Tib. Serlingpa, ), and the Indian teacher Dharmarakṣita, a prominent teacher at Odantapuri and author of a text called the Wheel of Sharp Weapons. Both these texts are well known in Tibetan translation. Atiśa's third major teacher of lojong is said to have been the junior Kusalī, known also as Maitrīyogi. Atiśa journeyed to Sumatra and studied with Dharmakīrtiśrī for twelve years.