1969: Apollo 11 moon landing is successful.
1972: Apollo 17 finds remains of an ancient Mars civilization on the moon's surface. In the remains an instantaneous teleportation device, using previously unknown technology is uncovered, giving humanity the ability to travel between Mars & back.
This device came to be called a "hypergate".
1975: Under international guidance, plans to colonize Mars were drawn up, and the Mars Treaty was made. The treaty was ratified by all the U.N member countries, and they agreed to not use military forces on Mars, and such. Following this, the Cold War was for all intents and purposes finished. This same year, the First Mars Survey Corps was deployed.
Prof. Leylegaria (unsure of the right romanization) followed with them as the official overseer.
1980: Immigration starts and 340,000 settlers are sent to Mars.
Starting in 1982, Rayregalia starts inciting anti-Earth sentiments among the Martian settlers, calling for an armed uprising. The UN immediately moves to suppress the situation, but the situation escalates. They later arrest Rayregalia, but a mob attacks and breaks him out of jail.
1985: Vers Empire formed, with Rayregalia named as the first emperor. In fear of the empire, the countries of Earth form the Earth Federation and enter a cold war with Mars. Things are relatively peaceful for the next decade.
1996: Martian terrorists bomb several cities, killing 3,267 people, causing hostilities between Earth and the Vers Empire to increase rapidly.
1997: Rayregalia steps down as emperor due to illness, and his son Gilzeria takes the throne.
1999: Gilzeria declares war on the Earth Federation. The Vers Empire fights using mechs called Cataphracts. During a battle on the moon the Hypergate goes out of control and destroys half the moon. Pieces form the Satellite Belt around Earth, and some crash into the Earth in an event called the Heaven's Fall. Earth is still rebuilding from that. During the battle Gilzeria is killed in action, causing Rayregalia to retake the throne and is still emperor as of the series' start. Gilzaria's daughter Princess Asseylum is born.
2000: A ceasefire is signed by both signs, and a demilitarized neutral zone is formed.
2003: Earth finished developing its own Cataphracts and first uses them to quell the rioting caused by Heaven's Fall. The riots are stopped in 2007 and things return to relative peace. Steps are made between Earth and Mars for peace.
2007: Post-war clean-up on Earth finishes. Conditions continue to stabilize.
2010: 10 years after the war. In every Earth country memorial ceremonies & top-level meetings are held, as both sides begin to march toward peace.
2014: In the name of peace, Earth takes a growing interest in the Vers Empire. The peace negotiations are expected to continue.