In the relations between the state and tax payer the legal maxim in dubio contra fiscum is of fundamental meaning. Although it has been formulated in Latin, its roots don’t reach the times of the ancient Rome. It was built in the modern era as a paraphrase of one quote taken from works of the Roman lawyer Modestinus. However, the first legal document in which there is a clear postulate to favor tax payers in the court proceedings is a letter written by the Otrogothic king Theodoric to a certain Marcel, who was holding the post of advocatus fisci at his court.