Hi long time no see
I can't believe I never noticed this, but Sanji's childhood story especially the part where he is imprisoned in a mask resembles the The man in Iron Mask movie story?
The masked person identity was a twin brother of the French king Louis XIV, who later became King after the three musketeers subdued him (if I recall correctly)
And Sanji, as we know, is French and from a royal bloodline AND was imprisoned with an iron mask to hide his identity
Oda will no way make this identical reference to this story for no reason