Complex sentence: Since the Acts of Union in January 1801, Ireland had been part of the United Kingdom with executive power lying in the hands of the Lord Lieutenant of Ireland and Chief Secretary for Ireland, appointed by the British government.
Split into simpler sentences: Since the Acts of Union in January 1801, Ireland had been part of the United Kingdom. Executive power lay in the hands of the Lord Lieutenant of Ireland and Chief Secretary for Ireland, who were appointed by the British government.