The planetary solar system around HO Librae (also known as Gliese 581) was discovered in CE 2007, several hundred years ago. At the time we knew very little about planet formation because we were limited to what we could observe within our own solar systems
In 2214, during the wane of the Conquest era, a Seedship was dispatched to HO Librae on a colonisation mission. Since it had been discovered, the planetary system had received six probes which had transmitted copious amounts of detail about the system, it's planets and other resources. It took forty years for an unmanned probe to reach HO Librae at 0.1G and twenty years for the messages to return by tight-beam transmission. Only one of the major corporations at the time had the presence in space and the will to strike out in a bold manner.
The journey to HO Librae would have taken over a hundred years at 0.01G acceleration using the most advanced antimatter drives of the time. And the Seedships carried a robotic crew using the most advanced artificial intelligences of the era. Aboard the vessel they carried a hundred thousand zygotes of their best, brightest and most powerful. And they carried all of the technological and social knowledge of their day. By our standards, the Seedship was more like a warship, with a huge amount of armour and firepower for the time, especially considering that there was no evidence of alien life anywhere in the Galaxy. They went prepared for war and it would be hundreds of years before they found it.
HO Librae c was not an Earthlike paradise, this much they knew. Rocky cored, much like Earth, it had lands and oceans. It had plants and some animals, the atmosphere did bear oxygen but at much lower percentages. The poles were a frozen hell and the equators were reminiscent of tundra, with constant permafrost. The gravity was heavier and the air was thick with cloud. And there, without the bounds of law, the Conquest Society thrived.
By the time the Earth had healed from the excesses of wars over resources and land, Human Unity had no knowledge of the Conquest Society. They built their Explorer craft and followed the guidance of the Traders in traveling the Wormhole networks. Hostilities were not expected and even so, all defences were centered on the wormholes. It would therefore be completely surprised when the first attacks came truly from the stars.
They attacked hard and swift but in the end their lines were too extended and they were forced to retreat. Human Unity lost a lot of people and craft in the short conflict including two Experts and one Explorer craft. From later experiences it was learned that the craft and Experts were captured and not destroyed. The Conquest Society now had a Key and it would not be long before we would hear of them again.
[Reference: Gliese 876d]