"[...] solitude became dear to [Muhammad (s)], and he would go for spiritual retreats to a cave in Mount Hira not far from the outskirts of Mecca. [...] retreat had been a traditional practice amongst the descendants of Ishmael, and in each generation there had been one or two who would withdraw to a solitary place from time to time so that they might have a period that was uncontaminated by the world of men." --- Martin Lings, 'Muhammad'