Complex sentence: The Gaels tended to be experts in guerrilla ambush, constructing forts in the woods which were used as hidden supply bases, connected by secret cleared paths and the like, the armies would move through the woods at great speed and frequently avoid open battle.
Split into simpler sentences: The Gaels tended to be experts in guerrilla ambush, constructing forts in the woods which were used as hidden supply bases, connected by secret cleared paths. The armies would move through the woods at great speed and frequently avoid open battle.