The history of the species was unknown with only artifacts left behind as proof of their existence. One of their colonies was the cold dead world called Faramond. Archaeologists examined the ruins and wondered why the ancient civilization made a base on the planet. There were no structures of any kind on the planet that supported a spacefaring civilization which further added to the mystery.
It was eventually discovered that the planet Faramond was actually an advanced piece of Old Culture technology. The planet's cold core was required to hold controls for an advanced long range transporter that worked on a frequency focused method allowing for long range travel to anywhere. Using this technology, the Old Culture engaged in a massive exodus to parts unknown. Along the way, they took key components from the planetary transporter super conductor which prevented others from following them to their destination. (TOS novel: Best Destiny)