Which body they associate with depends on their particular task in the physical world, spiritual levels of the bodies of predecessors and so on. The concept relates to the wider processes of history in Kabbalah, involving Cosmic Tikkun (Messianic rectification), and the historical dynamic of ascending Lights and descending Vessels from generation to generation. The esoteric explanations of gilgul were articulated in Jewish mysticism by Isaac Luria in the 16th century, as part of the metaphysical purpose of Creation.