On the plaque it says, "Dedicated to all Irish guardsman, Past, Present and Future - QUIS SEPARABIT"

Quis separabit is a Latin word meaning 'who shall separate us?' It is also a motto of The Order of St. Patrick, North Irish Horse, the Irish Guards, Royal Dragoon Guards and The Royal Ulster Rifles. The phrase quis separabit is also written on the Seal of South Carolina.