Complex sentence: As enduring units, they were able to become more effective fighting forces; more importantly, they could now form lasting loyalties to their commanders, as the typical 1-year consul system began to break down and generals served for greater durations.
Split into simpler sentences: As enduring units, they were able to become more effective fighting forces; more importantly, they could form lasting loyalties to their commanders. The 1-year consular system began to break down and generals served for greater durations.