When did duty-free allowances start? In which country and why? I am specifically asking about travellers being able to bring in alcohol and tobacco without paying duty or tax.
To be clear, I am asking about being allowed by law, rather than convention or customs people looking the other way.
This is related to my question on the politics stack.
I would like to know how explicit duty free allowances were introduced; a history of duty free.
Edit: MCW has provided information about the first duty free shop, which although informative doesn't quite answer what I wanted. I am interested in the destination country allowing people to bring in goods. I have tried using a search engine to find this out, but all I ever get back is contemporary information regarding import limits. There presumably is legislation allowing this in most countries.