"Mars will never be free until the sands run red with Earther blood."
- – Slogan of Free Mars
The Mars Resistance has been active on Mars in one form or another almost since the colony's foundation.
In 2243, the Free Mars movement started out as a peaceful political initiative to achieve Martian independence through political means. A lack of sympathy on Earth and increased exploitation of the colony from Earth-based corporations resulted in the organisation being co-opted by more militant factions, and resorting to acts of terrorism to make its message heard. One of the most notorious leaders of Free Mars was Abel Horn, who gained notoriety when he claimed responsibility for the destruction of Ritchey Station. 
Following the Earth-Minbari War, with the Alliance's infrastructure in ruins, food shipments that were already tightly rationed were cut off entirely in November 2250 by order of the Earth Senate, over the objections of EA President Elizabeth Levy. Always a powder keg of tension, the Martian population believed Earth had given priority to the wants of its own citizens at the cost of the needs of the colony world as punishment for declaring themselves neutral during the conflict. What followed was a planet-wide riot, lasting from January to April of 2251. Though Earthforce was eventually able to put down the riot, thanks mostly to the re-enforcements from Station Io, the animosity between the colony and Earth would only grow with time.
2257 saw a rapid increase in independence movements on Mars, some even more radical than Free Mars. A number of incidents followed including an attack on Station Phobos in 2258. Opposition finally gave way to open rebellion when the resistance raided a reserve military base, captured heavy weapons, and attempted to usurp the Earth controlled government. This lead to a total communications black-out and several days of prolonged fighting in and around the capital in Solis Planum. Though at first unwilling, President Luis Santiago eventually bowed to pressure to use force in subduing the population by ordering elite shock troops to secure the capital. It was during this time that Abel Horn, the most notorious leader of Free Mars, was killed when his ship was shot down by the EAS Pournelle over Phobos. After the fighting had died down, a new Mars Provisional Government was formed, headed by Xavier Montoya.  In December President Luis Santiago visited Mars a part of a goodwill tour of the outer planet colonies, presumably in the hopes of rebuilding relations with the Mars Colony. 
Resistance Under Clark
After the death of Luis Santiago and the destruction of Earthforce One at the Io Transfer point, the newly installed President Morgan Clark did little to ease tensions between Mars and Earth. In late 2259, with the aid of the Anla'Shok, the Mars Resistance uncovered a secret Psi Corps sleeper program while one of their best agents was on an intelligence gathering mission in Syria Planum. In 2260 the Resistance found new life and a swell in its ranks (including serving Earthforce personnel) at the onset of the Earth Alliance Civil War. Following President Morgan Clark's Martial law decree, along with the subsequent bombings and planetary blockade, the Mars Provisional Government declared independence from the Earth Alliance in protest over the martial law decree. Clark's crackdown was harsh, with open battles across the planet, a planetary embargo and communications jamming in effect, though with news outlets such as ISN now directly under EarthGov control, very little about what was really going on was known outside of Mars itself. By the spring of 2261, 259 days since the Mars declaration of independence, the resistance had lost control of 75% of the planetary surface with the capture of New Vegas and Flinntown. At this time the leader of the resistance was Tessa Holloran, better known as Number One due to the resistance's practice of using numerical codenames for their top members. There was also a Number Two, Number Three, etc. Though driven underground, in December of 2261 the Resistance movement proved to be critical in the rescue of John Sheridan from Clark's forces and disabling the fleet loyal to Clark in orbit above Mars in the final assault led by Sheridan. During the battle, resistance members successfully infiltrated and captured several Earthforce ground bases. 
With the defeat of the Clark Regime and as a condition for the Earth Alliance's membership in the newly formed Interstellar Alliance, the political independence of Mars was finally recognised by EarthGov.  Many former members of the Resistance found themselves as leaders in the newly reformed Mars Provisional Government and quickly set about establishing Mars as an independent power and hunting down the corporations that had been exploiting Mars and its population for generations. However, since some in Earth Dome were considerably less than happy with losing the former colony, the new government found itself repeatedly frustrated by Earth bureaucrats and red tape. ISA President Sheridan helped correct this situation by granting Mars an embassy on Minbar independent of the Earth embassy. He also chose Tessa Holloran to replace Michael Garibaldi as head of ISA Covert Intelligence, giving her access to information that helped clamp down on corruption by Earth-friendly Mars businesses.
Known Members Of The Mars Resistance
- Tessa Holloran - 'Number One' (Circa 2259 - 2261). 
- Real Name Unknown - 'Number Two' Circa 2261. Former Gropo during the Earth-Minbari War. 
- Amanda Carter - Member of the pre-militant 'Free Mars' movement. 
- Abel Horn - 'Free Mars' (2243 - 2258). 
- Lyta Alexander - Briefly worked with the resistance after escaping the Psi Corps in 2259 and again when working for Sheridan's forces in 2262. 
- John Demeter - 'Captain Jack', Mars Resistance contact. Implanted with a Drakh Keeper circa 2261.
- Derek - Ranger working with the Mars Resistance in 2259. 
- Donovan - A senior member, based on Earth. 
- Ensign Kelley - Mars Resistance contact for the main Earthforce staging area on Mars. 
- Lee - One of the Resistance's best men, killed on an intelligence gathering mission in Syria Planum. 
- Phillipe - Mars Resistance member Circa 2261. 
- ↑ 1.0 1.1 1.2 1.3 A Spider in the Web
- ↑ 2.0 2.1 The Official Babylon 5 Magazine: Volume 2, Issue #1 (July 1998) - Page 26 (Babylon 5's Mars Chronology)
- ↑ To Dream in the City of Sorrows
- ↑ A Voice in the Wilderness, Part I
- ↑ A Voice in the Wilderness, Part II
- ↑ Chrysalis
- ↑ Severed Dreams
- ↑ The Illusion of Truth
- ↑ 9.0 9.1 9.2 9.3 Racing Mars
- ↑ 10.0 10.1 Endgame
- ↑ Rising Star
- ↑ Objects in Motion
- ↑ 13.0 13.1 The Face of the Enemy
- ↑ 14.0 14.1 14.2 Divided Loyalties
- ↑ 15.0 15.1 Lines of Communication