Scholarly editing requires to associate various forms of epistemic status with facts, which is interesting to model formally from the viewpoint of artificial intelligence. Consider for example a creation date associated with written communication: it can be given by its author or can be inferred – by the editor or by a machine, it can be only partially specified by the author, it can be specified with different precision, considered as a point or range in time, etc. The current version of <hi xmlns="http://www.tei-c.org/ns/1.0" rend="italic">TEI</hi> offers some related elements to indicate certainty, precision and responsibility (The TEI Consortium 2015: Chapter 21), but these are not based on any formal semantic treatment and it is seems hardly possible to express the sketched date examples with them.