Article 18. [Provisions to secure protection of law]

(4) No person shall be held to be guilty of a criminal offence on account of any act or omission that did not, at the time it took place, constitute such an offence, and no penalty shall be imposed for any criminal offence that is severer in degree or description that the maximum penalty that might have been imposed for that offence at the time it was committed.

Article 18. [Provisions to secure protection of law]

(8) No person shall be convicted of a criminal offence unless that offence is defined and the penalty is prescribed in a written law :

Provided that nothing in this clause shall prevent a court of record from punishing any person for contempt of itself notwithstanding that the act or omission constituting the contempt is not defined in written law and the penalty therefore is not so prescribed.

Article 22
Nullum crimen sine lege
1. A person shall not be criminally responsible under this Statute unless the conduct in question constitutes, at the time it takes place, a crime within the jurisdiction of the Court.
2. The definition of a crime shall be strictly construed and shall not be extended by analogy. In case of ambiguity, the definition shall be interpreted in favour of the person being investigated, prosecuted or convicted.
3. This article shall not affect the characterization of any conduct as criminal under international law independently of this Statute.