Star system in the Pegasus Galaxy where Atlantis was located for many thousands, and perhaps millions, of years. Lantea is the fourth planet from the system's star. Comprised of nine planets (the fifth ringed) and an asteroid belt, the system became the last target of the Wraith after the species had successfully spread through most all other populated systems in the galaxy.
The Lanteans who inhabited Atlantis were engaged in a protracted war against the Wraith, and as part of their defensive efforts established a number of weapons satellites in their home system. The Wraith eliminated all but one, located fifteen hours away from Lantea by Jumper.
While Earth's Atlantis expedition managed to repel a new siege of Atlantis by the Wraith, they did make the mistake of alerting the Asuran Replicators to the city's existence. Unable to withstand an attack from the Asuran satellite weapon they launched the city ship into space, leaving the Lantean System behind.
See also: The First Siege of Atlantis
The Defiant One - Sheppard takes a unit to an Ancient weapons platform recently detected on the long-range sensors, very near to another world in the Lantean system.
The Siege, Part 1 - Drs. McKay and Grodin take a Jumper into the Lantean System to repair a surviving weapons satellite.
The Siege, Part 2 - At Colonel Everett's request Sheppard explains the history behind the first siege of Atlantis, and how the Lantean system was the last to fall.
First Strike - Besieged by the Repicators, the expedition is forced to launch Atlantis and flee from the Lantean System.