Spartans

We nick-named them the Spartans, a ferociously technologically advanced race from another Solar System.  When they first contacted Earth, not only was their name impossible for humans to pronounce, but their goal was fairly incomprehensible as well.  Eventually, we learned enough of their language and they gained sufficient sophistication in English and Chinese, to reach a compromise.  They had the technology to build gates into so-called worm holes by collecting worm hole energy and boring into space and time.  This allowed very fast travel between solar systems.  Alas, their technological sophistication had come at a huge and horrible price: the complete eradication of the other intelligent species on their planet.  The Spartans were a warrior species, and had treated this other more nurturing species as serfs for centuries, but while the Spartans were building their first subspace gate, the Farmers as Earth called them, rose up in a rebellion and literally fought to the last child.

So, we called them after the ancient Greek state of Sparta, which was so focused on the military tradition, that today it is known only by means of other ancient Greek state's art and literature, because they left no culture behind them: only tales of conquest and discipline.

Their home planet was dying, and despite their brilliance, the Spartans knew that they were not constant enough to rebuild, let alone heal the soil.  After taking what they described as a soul searching of their entire culture, they set about creating gates onto various neighboring solar systems, hoping to find intelligent life forms with whom they could forge mutual, equal relationships, and keep both their culture and their race, alive.  They chose Earth because while there was obviously 1 human race, the cultures were widely varied, and the Spartans were impressed by Earth’s apparent interest in cultural exchange (museums, foreign embassies) and the handing on of sophistication and knowledge without enslavement (factories in China).

Humans were nervous at first, but with the unquenchable optimism of the Human Spirit, Earth came to formal agreement with the Spartans: colonization efforts of appropriate worlds.  First unmanned probes and later manned expeditions soon followed to explore these other places.