Complex sentence: In the upstate were a larger number of Tories, who joined the British forces, but the Williamsburg Presbyterians were not fond of the king, and were inclined to sit out the war, until the British made a tactical error.
Split into simpler sentences: In the upstate were a larger number of Tories, who joined the British forces. The Williamsburg Presbyterians were inclined to sit out the war, until the British made a tactical error.