Complex sentence: According to some sources it began through a scheme devised by Aemilius to goad the enemy into attacking first; the Romans made a horse without a bridle run to the enemy's bank and sent some men to pursue it to provoke the enemy into an attack.
Split into simpler sentences: According to some sources it begun through a scheme devised by Aemilius to make the enemy start the attack. The Romans made a horse without a bridle run to the enemy's bank and sent some men to pursue it to provoke the enemy into an attack.