Charles was lenient with Manfred's supporters, but they did not believe that this conciliatory policy could last. They knew that he had promised to return estates to the Guelph lords expelled from the Regno. Neither could Charles gain the commoners' loyalty, partly because he continued enforcing the despite the popes declaring it an illegal charge. He introduced a ban on the use of foreign currency in large transactions and made a profit of the compulsory exchange of foreign coinage for locally minted currency. He also traded in grain, spices and sugar, through a joint venture with Pisan merchants.