The dictionaries of Piedmontese language published in the first half of XIXth century show that the word miraco ‘miracle’ [mi'raku] (< lat MIRACULUM) is not only grammaticalized as a marker of unexpectedness, but develops the epistemic meaning of ‘maybe’, ‘probably’. This phenomenon is apparently a unicum among the romance languages, and it shows a communality with typologically distant languages which express the so-called category of mirativity. Starting from the analysis of the attestations in the literary texts of XVIIIth and XIXth century (mostly theatrical comedies written in vernacular), this paper seeks to explore how the semantic development of this peculiar marker with a transparent etymology can be included in the typological debate on the category of mirativity and its links with evidentiality and epistemic modality.