The aim of the following paragraphs is to assess the role of fiat copper coins within the cycle of negotiations and approvals concerning sovereign debt in Castile during the first 3 decades of the 17th- Century. The perception of unsound fiat money will be studied using primary sources. The attitudes of contemporaries towards the transformation of coins from quasi- commodity money into unsound fiat money will be featured within the context of Castile's legal and political framework, highlighting alternatives to a devaluation and suggestions to introduce types of currency other than fiat money
