Romanos I Lekapenos
Romanos I Lekapenos (c. 870–948) was the son of an Armenian peasant who rose from fleet commander to be Constantine VII's regent and co-emperor. In 919 he married his daughter Helena to Constantine, taking the title basileopator, and was crowned co-emperor in 920.
In 927 granddaughter Maria married Peter I of Bulgaria, sealing a peace. After heir Christopher died in 931, he kept Constantine above his sons.
In 944 sons Stephen and Constantine deposed and confined him to a monastery. When they threatened Constantine VII, Constantinople revolted and the brothers were exiled to their father, who died in 948.