The 18th century papal prohibition on usury meant that it was a sin to charge interest on a money loan. As set forth by Thomas Aquinas in the 13th century, because money was invented to be an intermediary in exchange for goods, it is unjust to charge a fee to someone after giving them money. This is because transferring ownership of property implies the right to use that property for its purpose: "Accordingly if a man wanted to sell wine separately from the use of the wine, he would be selling the same thing twice, or he would be selling what does not exist, wherefore he would evidently commit a sin of injustice."[36]