Rioni River
Constantine was a son of King Bagrat III of Imereti and brother of King George II of Imereti. He was opposed to his brother, George, who had him and his son Rostom cast in prison in 1583. After the death of George in 1585, Constantine attempted to disinherit George's young heir, Levan and seized the territory east of the Rioni River, including Skanda, Katskhi, and Argueti. Levan was able to reclaim these areas in 1587, but he had to buy peace by granting to his uncle a princely estate in Argueti.