Seosaimhin an Nathair obtained the crown in RE 2825 after her father Ard Righ Cian an Nathair stepped down from the throne and entered retirement somewhere in the eastern Low Muck. Since then, she has tried to follow her father's vision. Continuing to work not only for a more unified Inis Mona and Etomesto, but pushing forward the country's understanding of the world and its natural boundaries. In doing so, her first royal decree was the formation of the Monaian Royal Cartographical Commission under the auspices of the C.B.T Flotilla. This forced the C.B.T and the Red Manes to continue their cooperation under the Mhuir Accords and greatly placated the executive authorities of the Flotilla.
It was also only two years in to her reign that a strange new enemy arrived upon the shores of Inis Albeon, which was defended by the brave actions of a few hundred individuals until the main army and fleet could arrive. Ard Banríon Seosaimhin an Nathair, much like her mother and father, was several times advised to leave the frontlines. Each time she refused until the shores of the inisa were once again assured from invasion.