Complex sentence: In 1784, the entire United States Army comprised just fifty-five artillerymen at West Point and twenty five more at Fort Pitt (modern Pittsburgh), and for defense, the United States relied upon the state militias who disliked fighting outside of their own states.
Split into simpler sentences: In 1784, the entire United States Army comprised just 55 artillerymen at West Point and 25 more at Fort Pitt (modern Pittsburgh). For defense, the United States relied upon the state militias, who disliked fighting outside of their own states.