In the siege of Mons, the forces of the Grand Alliance were under the command of a king known in Northern Ireland and Scotland as King what ?
Siege of Mons (1691):  The outcome was not in doubt, but in a conflict dominated by siege warfare, neither the French army of King Louis XIV, nor the forces of the Grand Alliance under King William III, could bring about a decisive battle. William III of England:  He is sometimes informally known in Northern Ireland and Scotland as "King Billy".
King Billy