 Complete the following phrase:  Nothing else is known of Boris IIs life until 968, when he 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, who would now join forces against Prince Sviatoslav I of Kiev, whom the Byzantine emperor had pitted against the Bulgarians. In 969 a new 