Approximately 8000 BC, the civilization of that world, advanced beyond even 23rd century Federation capabilities, was cast into ruin by the return of a glacial age. At that time, a vast complex was constructed for the women, while the men remained on the surface. Within the complex, everything the women could need or want was provided, all administered by the Controller, an advanced computer that they revered. The women themselves existed at a low intellectual level. Doctor McCoy theorized that disuse of their intellectual faculties had led to atrophy.