Despite its arguable necessity, the Treaty of Coruscant was extremely controversial. Senator Gaul Panteer, heir to the Alderaanian throne, opposed the treaty and arranged Alderaan's withdrawal from the Republic in protest. Gaul was said to be secretly negotiating the terms of Alderaan's return, but he was assassinated before he could do so; his ailing mother, the queen, died days later in a mysterious crash, leaving Alderaan without a ruler and without Republic protection.
The ensuing power vacuum allowed House Thul‒now supported by the Empire‒to return from exile. With the nobility in chaos and a possible Imperial takeover on the horizon, Bouris Ulgo, a former Republic general, declared himself king. House Panteer challenged Ulgo's rule, but its estates were quickly overrun and destroyed. House Organa, still loyal to the Republic, opposed House Ulgo diplomatically until it could marshal its forces. It wasn't long before all-out war broke out between House Ulgo, House Organa and House Thul, with all three families and countless lesser houses vying for the Alderaanian crown.