Two milleniums before the Universal Century, the Earth was ravaged by the horrors of pollution, war and crushing over population. Desperate to save their planet, the governments of Earth joined forces to form a global Federation, combining their resources to create groups of vast cylindrical space colonies called Sides. Thses colonies could sustain millions of people in space, indefinitely. At the end of the 2nd millenium, humankind entered the age of universal century (U.C.), beginning a great exodus to space.
After 40 years of emigration (U.C. 0040), nearly half of the entire human population lived in space. These pioneers adjusted to their new lives and prospered. However, they soon discovered that the government on Earth still controlled their destiny. Yearning for sovereignty, the colonists began to demand their independence.
First led by the charismatic Zeon (Jion) Daiken who gained a tremendous following by denouncing the Earth's oppresive rule over the colonies. This was first called the Republic of Zeon (Jion) and consisted mostly of Side 3's inhabitants. The name was later changed due to the mysterious death if Zeon (Jion) Daiken.
These impressive war machines were first developed by the Zeon (Jion) Archduchy. They are run by utilizing fusion technology in compact reactors. The Moblie Suits (MS) were created to usher in a new method of combat. The Zaku was one of the first MS ever created.
Signed on January 31st U.C. 0079, preveted the use of weapons of mass destruction by either side (Federation and the Zeon (Jion) Archduchy). This was created due to the enormous amounts of civilian casualties (billions to be more precise).
*U.C 0079 is also known as the 1 year war. All I know is that this was when a LOT of things happened, including the creation of the 1st Gundam unit. This also is somewhat the backbone of the entire Gundam series.