Sviatoslav I of Kiev
In 968 Boris II, future emperor of Bulgaria, went to Constantinople again to negotiate a peace settlement with Emperor Nikephoros II Phokas, and apparently to serve as an honorary hostage. This arrangement was intended to put an end to the conflict between Bulgaria and Byzantium, which would now join forces against Prince Sviatoslav I of Kiev, whom the Byzantine emperor had pitted against the Bulgarians. In 969 a new Kievan invasion defeated the Bulgarians again, and Peter I abdicated to become a monk. In circumstances that are not entirely clear, Boris II was allowed to return to Bulgaria and sit on his father's throne.