In 1400, Constantine was sent as an ambassador to the Mongol warlord Timur Leng who continued a relentless war against the Georgians. Afterwards, he vainly demanded from his reigning half-brother George VII to make peace with Timur. In 1402, Constantine together with the prince Ioane Jakeli of Samtskhe submitted to Timur but never took part in the war against Georgia. He succeeded on the death of George VII as king in 1407 and launched a program of restoration of what had been ruined during Timur’s campaigns. Towards 1411, he allied with the Shirvanshah Ibrahim I and the ruler of Shaki Sidi Ahmed to counter the Kara Koyunlu Turkmen advance into the Caucasus. In the decisive Battle of Chalagan, the allies were routed and Constantine, his half-brother David and the Shervanshah Ibrahim were taken prisoner. In the captivity, he behaved arrogantly and the infuriated Turkoman prince Kara Yusuf ordered him, David, and 300 Georgian nobles to be executed. Kara Yusuf put Constantine to death by his own hand.