This paper argues that we should take into account the process of historical transmission to enrich our understanding of material culture. More specifically, I want to show how the rewriting of history and the invention of tradition impact material objects and our beliefs about them. I focus here on the transmission history of the mechanical calculator invented by the German savant Gottfried Wilhelm Leibniz. Leibniz repeatedly described his machine as functional and wonderfully useful, but in reality it was never finished and didn't fully work. Its internal structure also remained unknown. In 1879, however, the machine re-emerged and was reinvented as the origin of all later calculating machines based on the stepped drum, to protect the priority of the German Leibniz against the Frenchman Thomas de Colmar as the father of mechanical calculation. The calculator was later replicated to demonstrate that it could function 'after all', in an effort to deepen this narrative and further enhance Leibniz's computing acumen.