Originally, Mars was lifeless, at least from the point of view of humanity. However, since around 2001, a significant exile community of Zangali from Grimlahd had lived under the surface of the planet in its vast underground cave system, after fleeing the Nall invasion of their home planet. This, of course, was unknown to humanity, busy with its own Earth-based problems. In 2053, the Consortium Space Agency, acting for the Earth Planetary Consortium sent its first explorers to Mars and established the Ares Station on planet as a scientific outpost.
In the wake of the Genetic Devolution Virus on Earth, the Consortium decided that to make sure than mankind survived colonization of Luna and Mars was important; in 2137, the Eden Terraforming Complex was opened. However, construction of the complex required detonation of explosives, explosives which inadvertantly collapsed the cavern where a Zangali subterranean city was. This sparked the Mankind-Zangali War, which would culminate in Zangali terrorists setting off nuclear devices in Washington D.C., London, Capetown, Beijing and Moscow. The war ended in 2145 with heavy loss on both sides, with the end result being that both races were allowed to continue living on Mars, as long as the humans ceased terraforming operations. This, of course, began the construction of colony domes (most notably Nicholson Colony Dome) all over Mars as large amounts of humans emigrated from Earth, and would lay the foundations of modern Martian civilization.
As the Solar Consortium gave way to the Stellar Consortium, Mars’s many domed cities became stopover points for travelers heading to and from Earth. More importantly, however, were the vast mineral resources which became apparent as Martian prospectors drilled carefully underground. Soon, operations had been set up and Mars was on its way to become one of the premiere mineral exporters in the Consortium, alongside the reserves of the Alpha Centauri system which were becoming depleted as Centauri joined the Consortium. As the Consortium itself grew to encompass more worlds, both alien and humanoid, so did the planetary economy of Mars. Its citizens, despite having to mostly live in protected city domes (besides the forgotten Outbacker terraformers) had a very high standard of living. Other industries developed included controlled agriculture and technology manufacturing.
During this period, Martians culturally began to blossom into the unique planet that they would later become, with many aspects of later Republican institute and society visible. This included the adoption of Romanized names, adoration for classical values and to a lesser degree, the Religio Romana as well. Finally, the use of Martian Latin, which is in many way similar to classical Latin with a few key variations, begun to appear on the red planet. Many of the later big Martian families have their history rooted in this period.