This myth remained unassailably vital for a millennium — until the first signs of a further transformation of consciousness began appearing in the eleventh century. From then on, the symptoms of unrest and doubt increased, until at the end of the second millennium the outlines of a universal catastrophe became apparent
Jung argues that the Christian God-image sustained collective consciousness for exactly one millennium before its internal instability began generating symptoms of dissolution that crescendo at the close of the second millennium.
, Memories, Dreams, Reflections, 1963thesis