A cosmic event in the ancient past. Gurdjieff explains this in his "All and Everything."
“The point is, that before this terrifying cosmic event of which I am speaking, the sacred Theomertmalogos which issued from the Most Most Holy Sun Absolute was still in a pure state without the admixture of any extraneously caused arisings whatsoever with their own subjective properties, and when this sacred Theomertmalogos came into the spheres of those planets on which the sacred crystallizations arose and from the results of the transformations of which higher being-bodies were coated and perfected through beings-apparatuses, then these latter received their presences exactly as they had to, to correspond to the required conditions of existence in the sphere of the Most Most Holy Sun Absolute. [...] But afterwards, when the mentioned common-cosmic misfortune occurred, on account of which the sacred Theomertmalogos began to issue from the Most Most Holy Sun Absolute with the admixture of subjective properties of extraneously caused arisings, then from that time these sacred cosmic arisings ceased to have the possibility of corresponding to the required conditions of existence in the sphere of the Most Most Holy Prime-Source." - Gurdjieff