The French had a considerable influence on The Royal Mint, with workers and engravers from France contributing to the mechanisation of the minting process in Britain. Both mints co-operated on coinage contracts between the First and Second World Wars but one of the more unusual episodes was the striking of the French gold Louis d’or coins at The Royal Mint in 1815. The government stressed they were official, claiming approval by Louis XVIII who was living in exile at the time, but the French authorities saw things differently, insinuating that they had not been made to the correct standard and were therefore not legal tender. Following the accusations, their accuracy was tested at the Trial of the Pyx and they were shown to be correct to the French standard.