This paper contributes to the growing research on lexically partly fixed and partly open phraseological constructions that allow for the productive formation of new instances. A crucial question is how one can determine the degree to which a given phraseological construction serves as a productive pattern for the formation of new instances. Stumpf (2016) suggested drawing a distinction, on empirical grounds, between modificatory patterns that allow for occasional substitution of a lexical position, and true phraseological schemata whose open slots are varyingly filled on a regular basis. Following this proposal, we examine in this paper the filler potential of the German phraseological construction [X kam, sah und Y] ‘X came, saw, and Y’, carrying out slot analyses with the open source corpus linguistic tool Lexpan (Steyer and Brunner 2014; Steyer 2018). Contrasting the construction with its Latin equivalent [veni, vidi, X], we show that while both constructions are productively used in German and allow for a variety of fillers, [X kam, sah und Y] has the status of a true phraseological schema, while [veni, vidi, X] is to be classified as a modificatory pattern.