Simplify the following text for a Grade 9 native English-speaking person.
Original: All this was evidently much to the surprise of the Persians ; Passing through the hail of arrows launched by the Persian army , protected for the most part by their armor , the Greek line finally collided with the enemy army .
Simplified: Passing through the hail of arrows launched by the Persian army , protected for the most part by their armor , the Greek line finally collided with the enemy army .