Andal Invasion and Kings of Mountain and Vale

The founding of House Arryn would occur in the Coming of the Andals, when the Andals would first overrun Westeros, beginning their invasion at the Vale, where the First Men were already in disarray, with some even joining the invaders instead of opposing them as a unified force, with the control of the First Men waning after each conflict with the Andals, where they finally united behind King Robar Royce, the and the Andals uniting behind Artys Arryn, the Winged Knight