AC 001: Several nations establish permanent space stations in low Earth orbit. This is the first year of the After Colony (AC) calendar.

AC 022: Construction of space colonies begins at Lagrange point 1. The project is complicated by difficult working conditions
and conflicts between the sponsoring nations, and work proceeds very slowly.

AC 050: Earth's nations begin abandoning the troubled colony project, until the oil-rich countries of the Middle East decide to
invest in the effort. Colony construction begins at Lagrange points 2 through 5.

AC 070: Disputes break out among Earth's nations, due to a shortage of colony construction materials. The Middle Eastern
nations intercede and negotiate an end to the conflicts. Construction resumes, using asteroids as raw material.

AC 102: An Island 2 type colony is completed at Lagrange point 1. Soon there are population centers composed of
multiple colonies, popularly known as "colony clusters." As international disputes flare up on Earth, people escape these
conflicts by emigrating to the colonies, and soon much of the human population is living in space.

AC 133: Earth's warring nations finally negotiate a peace agreement, forming the "United Earth Sphere Alliance."
In order to keep the peace, and deal with nations that oppose the new world government, the Alliance Forces are established.
One of the Alliance's key supporters is the military-industrial combine called the Romefeller Foundation.

AC 140: One by one, Earth's nations join the Alliance. As their mother countries join, the colonies are also enrolled, willing or not.
The colonies are critical of the Alliance and its intentions, and the Alliance decides to respond with force in order to silence its critics.

AC 147: In the name of peace and justice, and under the authority of its member nations, the Alliance forcibly seizes control of the space colonies.

AC 149: The Alliance assembly transfers control of the once-independent colonies back to the countries that originally constructed them.
These nations then kindle a new colony emigration boom.

AC 165: In order to peacefully oppose the Alliance, the citizens of the colonies choose Heero Yuy as their representative. His charismatic leadership strengthens solidarity between the colonies.

AC 170: Colony leader Heero Yuy proclaims policies of demilitarization and non-violence, which are well-received by many of Earth's nations.

AC 173: OZ, a subsidiary of the Romefeller Foundation, begins development of humanoid weapons known as "mobile suits."

AC 174: Colony leader Heero Yuy makes a goodwill tour of Earth's nations, laying the groundwork for colonial independence.

AC 175: On April 7, colony leader Heero Yuy is assassinated by an unknown gunman. The leaderless colonies are thrown into chaos, and the Alliance plans a second military intervention.

AC 176: The Romefeller Foundation begins production of military mobile suits. The Alliance forms the Special Mobile Suit Corps, or "Specials," made up of Romefeller Foundation employees. Under the pretext of suppressing the chaos in the colonies, the Alliance again sends in the military, and the new mobile suits are first used in combat. All space colonies are placed under military control, and communication between colonies is prohibited.

AC 182: The Alliance attacks the Sanc Kingdom, an advocate of Heero Yuy-style total pacifism. The capital falls in one day, and King Peacecraft is killed. The whereabouts of Peacecraft's children are unknown.

AC 193: Treize Khushrenada becomes leader of the secret society OZ, and commander of the Specials.

AC 195: On April 7, "Operation Meteor" begins. Each colony cluster sends an advanced Gundam mobile suit to Earth. After landing, the five Gundams begin attacking Alliance military bases and factories; their goal is to cripple the secret society OZ.