 Complete the following phrase:  Leo was apparently a relative to the ruling Macedonian dynasty, and a brother-in-law of the famed diplomat Leo Choirosphaktes. In 917, he was governor strategos of the theme of Dyrrhachium, and was sent to the Serbian ruler Petar Gojniković r. 892917 to persuade him to attack Simeon I of Bulgaria r. 893927, with whom the Byzantines 