This article analyses the relationship between the principle of legality in criminal law and the judge-made formation of criminal offences, taking as its starting point the European Court of Human Rights judgment in Contrada v. Italy (14 April 2015). The ecthr found a violation of Article 7 echr on the grounds that the offence of “concorso esterno in associazione mafiosa” (external participation in a mafia-type association) was not sufficiently foreseeable at the time of the relevant conduct. The article begins by examining the theoretical critique of legal logicism and the structurally creative nature of judicial interpretation, drawing on the contributions of Perelman, Troper, and Cappelletti, as well as on the Italian criminal law scholarship of Donini, Palazzo, and Di Giovine. It then reconstructs the ecthr’s “substantive” notion of legality and the requirements of accessibility and foreseeability as developed from Sunday Times to Del Río Prada. The analysis proceeds to scrutinise the resistance of the Italian legal order, as expressed in the Genco judgment of the United Sections of the Court of Cassation, which denied the extension of the Contrada principles to defendants in analogous situations through a series of argumentative strategies – the classification of Contrada as “nonconsolidated law”, the subjectivisation of foreseeability, and the negation of judgemade norm creation – each of which is subjected to critical assessment. Finally, the article identifies what it terms an “underground reception” of the Strasbourg principles in Italian case law: judgment No. 28594 of 2024 of the Sixth Section of the Court of Cassation applied the very logic of Contrada – prohibiting the retroactive application of an adverse judicial overruling – without citing the European precedent. This dissociation is argued to be revelatory of a systemic contradiction. The article concludes by addressing the unresolved theoretical question of whether foreseeability belongs to the category of typicality or culpability, and advocates for the development of a conscious and transparent framework of guarantees for judgemade criminal law.