The phenomenon of dwelling was a central research theme in architectural phenomenology. Much of the way it was understood in architecture was shaped by the later thought of Martin Heidegger as set in his influential essay: "Building Dwelling Thinking." He links dwelling to what he refers as the "gathering of the fourfold," namely the regions of being as entailed by the phenomena of: "the saving of earth, the reception of sky (heavens), the initiation of mortals into their death, and the awaiting/remembering of divinities." The essence of dwelling is not architectural, per se, in the same manner that the essence of technology for him is not technological per se.[13]