In first place, our porpose in this paper will be to examine the displacing carried out for Jacques Derrida of the Martin Heidegger's concept of Ereignis as "Sending of Being", from the ontology to the realm of postal technology. Secondly, we will see the consequences that derive from inscribing an ontological concept in a context governed by alterity, both for a genealogical view of intellectual history, as well as when illustrating the nature of the complex relationship between the two philosophers.