  It is nowadays common to consider that proof must be part of the learning of
mathematics from Kindergarten to University1. As it is easy to observe, looking
back to the history of mathematical curricula, this has not always been the
case either because following an old pedagogical tradition of rote learning
proof was reduced to the formalism of a text and deprived from its meaning or,
despiteits acknowledged presence anywhere in mathematics, proof did not get the
status of something to learn for what it is. On the long way from its absence
as such in the past to its contemporary presence as a content to be taught at
all grades, proof has had to go through a process of didactical transposition
to satisfy a number of different constraints either of an epistemic,
didactical, logical ormathematical nature. I will follow a chronological order
to outline the main features of this process with the objective to better
understand the didactical problem that our current research is facing.
