


After being appointed as the leader of the Republic of Zeon, Degwin Zabi adopted the title of Sodo, meaning "Lord", and was referred to from them on as Degwin Sodo Zabi. The people of Republic of Zeon took this to mean that Zeon Zum Deikun was naming Degwin to succeed him as leader of the Republic in UC 0068.

When the leader of the Republic of Zeon became gravely ill he mentioned only one name on his death bed, "Degwin Zabi". Three months later, in January UC 0079, the Principality of Zeon declared open war on the Earth Federation. In October of UC 0078, the Zeon entered a state of national mobilization, dividing their military into a Space Attack Force under the command of Dozle Zabi and a Mobile Assault Force under the command of Kycilia Zabi. Declaring themselves the Principality of Zeon a year later, and brutally purging Zeon Deikun's remaining followers, the Principality became increasingly hostile to the Earth Federation. Relations between the two had been tense since Side 3 declared themselves the independent Republic of Zeon under the leadership of Zeon Zum Deikun in UC 0058, and had only worsened since Deikun's death and the Zabi family's rise to power in UC 0068. The One Year War was a culmination of the hostility between Side 3's Principality of Zeon and the Earth Federation. The war ended on January 1, UC 0080, when the Republic of Zeon, reinstated after the defeat and isolation of the Principality, signed a peace treaty with the Earth Federation. The portion of the war depicted in the original anime, Mobile Suit Gundam depicts mainly the last few months of the "One Year War", where only the introductory narration mentioned the earlier events including destruction of multiple space colonies and the dropping of an Island 3 type colony from orbit, resulting in the destruction of half of the human population. A short period in the first week of the war is known as the "One Week Battle" or the "One Week War", in which most civilian casualties are accrued by the indiscriminate use of WMDs and surprise attacks.

The One Year War begins on January 3, UC 0079 (the Universal Century calendar begins some time after 2045 AD, according to the official timeline). The war is also known as the Zeon's War of Independence to the former soldiers of the Principality of Zeon. Its casualties, both military personnel and civilians were in the billions. The One Year War is the largest military conflict depicted in the Universal Century series, involving tens of thousand of mobile weapons, thousands of war ships and millions of combatants.
