A tulku (also tülku, trulku) is a Tibetan Buddhist lama who has achieved the ability to consciously determine to be reborn, often many times, in order to continue their Bodhisattva vow. The most famous example is the lineage of Dalai Lamas, who are said to be reincarnations of the previous thirteen Dalai Lamas, beginning with Gendun Drup (1391 – 1474). It is held in the Vajrayana tradition that the oldest lineage of tulkus is that of the Karmapas (spiritual head of the Karma Kagyu lineage), which began with Düsum Khyenpa (1110-1193).