The chapter examines the grammar and semantics of the expression of possibility in Amharic (Ethiopia). In particular, it will have a close look at the verb ʧalə which corresponds to the English modal ‘can’ in its many uses, including expressing ‘ability,’ ‘possibility,’ and ‘permission.’ However, when ʧalə ‘can’ occurs in the impersonal construction whereby the agent argument (the logical subject of the verb) controls object agreement in the compound imperfective, the construction so derived expresses the meaning of ‘possibility without obligation,’ i.e., the agent may carry out the action encoded by the main predicate if they wish but is not obliged to do so. The study shows how the availability of this impersonal interpretation of the verb ʧalə may partly explain the crucial discrepancy between the Amharic and Italian translations of Article 17 of the Treaty of Wuchale (1889). The data is drawn from a variety of sources including historical documents, naturally occurring discourse, complemented by the author’s own intuition as a native speaker. The paper aims to contribute to our understanding of the interaction between the lexicon and grammar in the domain of modality.