Principles of European Penology derive from art. 3 ECHR. These principles are embellished as positive obligations under the Convention. The reasoning of the ECtHR appears to be strongly inspired by soft law-instruments of the Council of Europe. This article elucidates the normative function of soft law within the ECHR by analyzing the Courts judgments on life imprisonment. It further embeds these instruments into the theory of interpretation of the ECHR thus answering the question whether the Court is hardening soft law through its jurisprudence.