Is it lawful to steal when you are in a condition of extreme need? Many theologians and canonists between the 12th and 13th centuries wanted to answer this question. It is not just a case of conscience. The problem of theft in case of need is linked to the idea of common possession of the earth’s goods and their distribution in case of extreme need. The paper traces the history of one of the most interesting debates in Christian theology, which led to the definition of the ethical-economic lexicon in the Middle Ages.