The Kormenian conquest started in the context of a "late or 'small' migration of peoples". Contemporary sources attest that the Kormenians crossed the Kalakea river following a joint attack in 894 or 895 by the Colomis and Beretians against them. They first took control over the lowlands east of the river Danuba and attacked and occupied Terepesos (the region to the west of the river) in 900. They exploited internal conflicts in the western city states and annihilated this state sometime between 902 and 906.