“Whom none could overcome with iron or gold.”
            As quoted by Cicero in De Re Publica, Book III, Chapter IV 
Iron is a metonym for sword/warfare, and gold for money/bribery.
        
Original
Quem nemo ferro potuit superare nec auro.
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Ennius 23
Roman writer -239–-169 BCRelated quotes
 
                            
                        
                        
                        “Everything has its limit - iron ore cannot be educated into gold.”
 
                            
                        
                        
                        “To have gold brings fear; to have none brings grief.”
English Proverbs (1659)
 
                            
                        
                        
                        Source: De architectura (The Ten Books On Architecture) (~ 15BC), Book VII, Chapter III, Sec. 5
 
                            
                        
                        
                        
                                
                                    “Not chaffering war but waging war, not with gold but with iron—thus let us of both sides make trial for our lives”
                                
                                
                                
                                
                                    
                                    Nec cauponantes bellum sed belligerantes;
Ferro non auro vitam cernamus utrique.
                                
                            
As quoted by Cicero in De Officiis, Book I, Chapter XII
 
                            
                        
                        
                        Source: The Self-Overcoming of Nihilism (1990), p. 180
 
                            
                        
                        
                        
                                        
                                        (28th February 1824) Metrical Tales. Tale I. The Three Wells - A Fairy Tale 
The London Literary Gazette, 1824
                                    
 
                             
                            