Complex sentence: James's viceroy Tyrconnell, commanding the main Jacobite army, blocked Schomberg's passage southwards but did not give battle and the two armies remained encamped opposite each other in very wet and cold weather for several weeks before they withdrew to winter quarters.
Split into simpler sentences: James's viceroy Tyrconnell, commanding the main Jacobite army, blocked Schomberg's passage southwards but did not give battle. The two armies remained encamped opposite each other in cold, wet weather for several weeks before they withdrew to winter quarters.