On 18 November 2010, the Court of Justice of the Economic Community of West African States (ECOWAS) held that legal reforms adopted by Senegal in 2007 to incorporate international crimes into the national Penal Code to enable its domestic courts to prosecute Hissene Habre for, among others, crimes against humanity committed in Chad twenty years before, violated the principle of legality, specifically the principle against non-retroactivity of criminal law. The court held that such crimes could be prosecuted only by a hybrid tribunal with the jurisdiction to try Habre for the international crimes based on general principles of law common to the community of nations. Some scholars opined that the ECOWAS decision was wrong, stating that the crimes in question were criminalised already under international law and that Senegal‟s legal reforms simply served jurisdictional purposes. Given that, as a core component of the principle of legality, the role of non-retroactivity is to prohibit the creation of new crimes and their application to past conduct, the opinions of such scholars may hold true. / Thesis (LLM (Human Rights and Democratisation in Africa)) -- University of Pretoria, 2011. / http://www.chr.up.ac.za/ / nf2012 / Centre for Human Rights / LLM