Complex sentence: But once this awareness materialized, the potential for terror that it created put pressure on emerging conceptions of reality so that any formation that was to be widely accepted by the masses needed to provide a means of managing this terror.
Split into simpler sentences: But once this awareness materialized, the potential for terror that it created put pressure on emerging conceptions of reality. Any conceptual formation that was to be widely accepted by the group needed to provide a means of managing this terror.