PRELIMINARY TITLE
On penal guarantees and on the application of the Criminal Law

Article 2

1. No felony or misdemeanour shall be punishable by a punishment that is not foreseen by Law prior to it being committed. Likewise, the Laws establishing security measures shall not have retroactive effect.

2. Notwithstanding this, criminal laws that favour the person found guilty shall have retroactive effect, even though final judgement may have been handed down and the convict is serving a prison sentence at the time of them coming into force. When doubt arises in determining the most favourable law, the prisoner shall be heard. However, offences committed while a temporary Law is in force shall be judged pursuant thereto, except for express provisions to the contrary.

Article 11
Jurisdiction ratione temporis
2. If a State becomes a Party to this Statute after its entry into force, the Court may exercise its jurisdiction only with respect to crimes committed after the entry into force of this Statute for that State, unless that State has made a declaration under article 12, paragraph 3.

Article 24
Non-retroactivity ratione personae
1. No person shall be criminally responsible under this Statute for conduct prior to the entry into force of the Statute.
2. In the event of a change in the law applicable to a given case prior to a final judgement, the law more favourable to the person being investigated, prosecuted or convicted shall apply.