Isaac Comnenus was oldest of two sons left by Manual and was crowned in his father's place and served long and faithfully, and after the decline of his health and vigor he urged his brother Johannes to take his place. This John refused to do and his action must be censured as a criminal desertion of duty and a rare offender against his family and country. The purple he refused was accepted by Constantine Ducas IX, a friend of the Comnenian line. He married Eudocia. She was regent on his death and married Romanus Diogenes, who was next Emperor.