Complex sentence: The horde, led by Khan Temir, approached the Commonwealth in May, and hetman Stanisław Koniecpolski gathered forces to stop it; however his army was numerically inferior, and at first he could only carry out delaying actions.
Split into simpler sentences: The horde, led by Khan Temir, approached the Commonwealth in May, and hetman Stanisław Koniecpolski gathered forces to stop it. However, his army was numerically inferior, so that at first he could only carry out delaying actions.