The Imperial Romulan State came about as a result of political schism in the Romulan Star Empire following Shinzon's coup in 2379. Several groups vied for power, including those led by two of the group of conspirators that helped bring Shinzon to power; Commander Donatra, and Senator Tal'Aura - the latter who was made the new Praetor. Donatra retained control and support over much of the Imperial Fleet, and put her political allegiance with Braeg, her lover, a former admiral, and Tal'Aura's political adversary.
Braeg orchestrated civil unrest in Victory Square on Romulus to try and force Tal'Aura out of office. But Braeg's rebellion was crushed when Tal'Aura brought in heavy weaponry to quell the crowd, prompting Braeg to surrender rather than allow a massacre. For Braeg's treason Tal'Aura had him poisoned and thus cemented Donatra's hatred and opposition to her.
Donatra is supported by her fleet of Norexan class Warbirds, led by her flagship, the IRW Valdore.