Complex sentence: His father had been implicated in the 1641 Rebellion, supported the Irish Confederacy during the subsequent war, and assisted the Anglo-Irish Royalist forces against the English Republicans during the Siege of Dublin.
Split into simpler sentences: His father had been implicated in the 1641 Rebellion, and supported the Irish Confederacy during the subsequent war. He assisted the Anglo-Irish Royalist forces against the English Republicans during the Siege of Dublin.