Complex sentence: Maurice's force numbered 10,000 infantry and 3,000 cavalry with numerous artillery and a large supply train-they arrived in quick time since the army was transported mostly by boat on land and sea.
Split into simpler sentences: Maurice's force numbered 10,000 infantry and 3,000 cavalry with numerous artillery and a large supply train. They arrived in quick time since the army was transported mostly by boat, on land and sea.