The Ancients are the most advanced known race in the Stargate Universe, and are the creators of the Stargate, the central object in the franchise. They are known as Ancients in Milky Way, and Lanteans or Ancestors in Pegasus, and have called themselves Anqueetas in their own language. The Ancients are arguably the most influential race in the series, with their actions in the past shaping nearly every event shown in the series. They have ascended to another plane long ago, but their technology and artifacts are still a point of conflict between many races. They have also had a hand in the creation of humanity. The Ancients are also connected to every antagonist in the show: They created the Asurans and the Wraith, they were once the same race as the Ori, and the Goa'uld rose to their dominance by scavenging their technology.
The Beings known as Alterans evolved in their home galaxy probably while the dinosaurs still walked the Earth. They were once one race, but as their species progressed, philosophical differences began to appears between the two fractions which would later be named Ori and the Ancients. The Ancients turned to science and respect of others, while the Ori turned more towards religion. Eventually this would have turned into an all-out war. Unwilling to fight against their brethren, the
peaceful Ancients left their home galaxy and eventually settled in the Milky Way, where they made a wast Empire.
The Ancients created the Stargate network in the Milky Way, which they called Avalon, connecting thousands of Worlds together. The oldest Stargate known is located on Earth or Terra, in the Antarctica outpost, which could mean Earth was the first planet they settled upon in Milky Way, and possibly even their capital. Earth was also the location of the great City-ship Atlantis.
Eventually the Ancients made contact with other races on a similar development level, and with them made the Alliance of Four Great races. their Empire flourished, and in time, they began to do research on Ascension, a way to shed your physical body and exist as pure energy on another plane.
However, the Ancients were struck by a plague against which they could find no cure (the plague was possibly created by the Ori). Faced with oblivion, some decided to ascend, while many decided to migrate in their city-ships like Atlantis to the Pegasus galaxy. There they made another empire and continued to advance.
Before they left for Pegasus, the Ancients influenced the evolution of Humanity, causing them to evolve in the same way as the Ancients themselves. This is why the Alterans are considered the first evolution of humanity. The Ancients also created Humans in Pegasus , and seeded them on many worlds across the galaxy. They also seeded Stargates, just like in Milky Way.
But, in Pegasus the Ancients, now calling themselves Lanteans, encountered the Wraith, a vampiric species which considered them and humans food. In a rare moment of imprudence, the Lanteans decided to try and negotiate with the Wraith. The Wraith responded by slaughtering their delegation, and thus a war began.
Though the Lanteans were vastly technologically superior to the Wraith, eventually the sheer numbers ensured the Wraith victory, until only Atlantis survived out of all Lantean colonies, protected by its powerful shields. The Lanteans abandoned Atlantis in Pegasus and returned to Earth through the Stargate. There they interbreed with primitive Humans, giving them the gene needed to activate ancient technology.
Eventually the last of the Ancients ascended, leaving the Milky Way and Humanity to fend for themselves. However, in the ascended plane they once again encountered their old enemies, the Ori. The
Ori have also ascended and now intended to make all lesser races worship them as gods.This went against the philosophy of the Ancients, so the once again went to war. The two factions are locked in eternal combat, and while that is true, the Ori cannot directly manifest in the mortal plane.
Recognizing the danger the Ori might pose, Ancient scientist named Moros created a device which would destroy the Ori, called the Sangraal, but the others never allowed him to finish it because it went against their beliefs about the respect of other beings. Recently, the Humans of Earth, or Tau'ri, have completed the device and launched it into the Ori galaxy ,where it destroyed the Ori and ended the conflict once and for all.
Before they ascended, the Ancients were strikingly similar to ordinary humans, except possessing a relatively more advanced physiology. This is because the human evolution was guided by the ancients to match their own evolution, thus creating a sort of "children race". The Ancients did the same thing with the humans in Pegasus.
As they progressed on their way to ascension, the Ancients evolved telekinetic powers and other advanced abilities.
After they ascended, the Ancients became beings of pure energy and great power. They were able to lay wast to whole civilizations, affect weather, and had infinite learning potential. They became the arguably most powerful race in the universe, but also denied themselves any right to manifest in the lower planes due to their own philosophy.
The Ancients are fierce believers in free will and will interfere in other affairs not even to save themselves. They are known to inflict great punishments, like wiping out civilizations and forcing transgressors back onto the mortal plane to enforce this rule. However, it is not known how strict this rule is, since it is known that interfering "a little bit" is allowed. how much interference exactly is tolerated is not known.
This philosophy is in contrast with their cousins, the Ori, which state that those who do not share knowledge with the lower planes are evil, and must be destroyed. Therefore the Ori and Ancients have been locked in combat until recently.
The technology of the Ancients is the most advanced in the known universe, far surpassing even that of their brethren, Ori, and other great races. Only the latest technology of the Asgard is able to match them.
Their most famous creation is by far the Stargate, a device which can open a wormhole to any other Stargate in the network, allowing instantaneous travel between thousands of worlds.
There are also other Ancient feats of engineering include their city-ships, like the Atlantis, the Aurora-class warships, Drone weapons, Ring teleporters, DNA resequencer, Zero Point Modules and Inter-galactic hyperdrives.
All ancient technology require a special gene to activate it. This is called the ancient technology activation (ATA) gene, and was passed on to humans through interbreeding.