Joseph Davion became heir to the throne of the Federated Suns when Mary Davion, daughter of First Prince Roger Davion, was stripped of her right to the throne by the First Prince with the issue of the Act of Succession. Mary was stripped of her claim to the throne after she fell in love with and married Soto Kurita, brother of the Draconis Combine Coordinator, Takiro Kurita, in 2696. Mary acceded to the act, giving up her claim on the throne for the man she loved, and Joseph Davion was recognized as the official heir to Roger Davion.
The situation appeared resolved until Mary's death in 2715, at which point Takiro Kurita sent envoys to New Avalon and then the Star League High Council, declaring that Mary and Soto's son Vincent should be declared the actual heir to the Davion throne. First Lord Jonathan Cameron attempted to sideline the contentious issue, locking the issue of the succession up in various committees until the Coordinator ran out of patience and launched an invasion of the Federated Suns in 2725 to enforce his nephew's claim to the throne.
The invasion prompted a hasty counter-offensive on the part of the Armed Forces of the Federated Suns, which quickly began to collapse, prompting Joseph Davion to take to the field in his Marauder BattleMech. Joseph took command of the AFFS forces on Royal, but during the battle for Baron's Harbor Joseph's 'Mech suffered critical damage and was immobilized. Joseph's ejection system had also failed, leaving him to be captured by Draconis Combine Mustered Soldiery infantry forces; the DCMS troopers pulled Joseph from his cockpit, forced him to kneel and then beheaded him. The death of the First Prince shattered the AFFS forces on Royal, causing them to quickly retreat from the world.
Joseph Davion's death and the apparent inactivity on the part of the Star League as two member states openly fought a large-scale conflict prompted an internal coup within the Star League. The SLDF Commanding General, Ikolor Fredasa, attempted to persuade the sister of the First Lord to replace her brother, and when he failed in his attempt, Fredasa spread rumors of a coup to force the First Lord to act. Ultimately, Fredasa and a number of other high-ranking Star League officials were executed for treason, and Jocasta Cameron took an active role in governing the Star League. Fredasa's successor, Commanding General Rebecca Fetladral, launched Operation SMOTHER, a five Division strong SLDF deployment intended to seperate the AFFS and DCMS forces engaged in the War and restore order. This was ultimately successful, but the death of Joseph Davion and the length of time it had taken for the Star League to intervene in the War created great discontent and resentment within the Davion family.
|“||No Davion ever backed down from a fight. I'm not going to be the first one to change that, not if the whole bloody Star League decides to crash the party.||”|
|— Prince Joseph Davion, on hearing of the violation of the Genoa Resolution, 2725|
Title and Position
|First Prince of the Federated Suns
| Succeeded by|
- Handbook: House Davion, p. 111, "Leaders of the Federated Suns"
- Historical: Liberation of Terra Volume 1, p. 16-18, "A Plague On Both Your Houses: The War of Davion Succession (Second Hidden War)"
- House Davion (The Federated Suns), p. 53, "Beginning Of The End"