 Money changers were active in Paris since at least 1141; they knew the exact values of all the different silver and gold coins in circulation in Europe.They had their establishments primarily on the Grand Pont, which became known as the Pont aux Changeurs and then simply the Pont au Change.Tax Records show that in 1423 the money changers were among the wealthiest persons in the city; of the twenty persons with the highest incomes, ten were money changers.