Complex sentence: During the late 9th and early 10th centuries, Simeon I achieved a string of victories over the Byzantines, and was recognized with the title of Emperor, and expanded the state to its greatest extent.
Split into simpler sentences: During the late 9th and early 10th centuries, Simeon I achieved a string of victories over the Byzantines. For this, he was recognized with the title of Emperor, and proceded toexpanded the state to its greatest extent.