Complex sentence: Before that, Elemag as one of the generals of the King of Bulgaria Samuel, killed Gregory Taronit in a duel-Gregory was the leading general of Emperor Basil II in the fight against the Byzantine army outside Thessaloniki in ~ the year 999 AD.
Split into simpler sentences: Before that, Elemag was one of the generals of the King of Bulgaria Samuel. He killed Gregory Taronit in a duel-Gregory was the leading general of Emperor Basil II in the fight against the Byzantine army outside Thessaloniki in ~ the year 999 AD.