Based on an experiment carried out with 10- to 11-year-old pupils, this paper questions the place of imagination in a class activity using the history of mathematics. The study focuses on three groups of pupils who were offered three variants of the same activity based on base-60 counting (our time measurement system inherited from the Babylonians). To identify differences and similarities between the three scenarios, a quantitative analysis, using a Principal Component Analysis (PCA), was carried out on the basis of the pupils' productions and a questionnaire. The approach remains exploratory, but it seems to indicate that imagination plays a relevant role in sessions using history of mathematics.