Sumbat III of Klarjeti, a son of Bagrat (died 988), son of Sumbat II of Klarjeti, had succeeded upon the death of his childless paternal uncle David II as the sovereign of Klarjeti, a position which he had shared with his brother Gurgen.
The tenth-century Georgian chronicler of the Bagratids, Sumbat Davitis-Dze, accords them a royal title—klarjni khelmtsipeni.
Sumbat and Gurgen had ruled over a portion of the hereditary Bagratid territory which remained outside the control of their distant cousin Bagrat III, who had become a king of a unified Georgia in 1008.
In 1011, the brothers are invited by Bagrat to negotiations at the castle of Panaskerti, but are arrested and held captive in the castle of Tmogvi, where they are soon put to death.
Their possessions pass to Bagrat and his progeny.
Their children—Bagrat, son of Sumbat, and Demetre, son of Gurgen—flee to Constantinople, whence they will try to retrieve patrimonial lands with imperial aid, for the last time in 1032, but to no avail.
