In the introduction to The Paths of Heidegger's Life and Thought Otto Pöggeler says that:

If we were to mark the most prominent phases of the thinker's career, we would have to distinguish: 1) the question of the meaning of being in Being and Time, 2) the question of truth as history in the following decades, and 3) the question of place as a way of addressing our place, in his late work. In between lie manifold documents in which the unified course of Heidegger's path of thought can be seen.

Why, then, isn't the continuity of Heidegger's thought obvious, rather than held to be sharply divided in two by a reversal?...Heidegger personally testified that the term Ereignis, or emergence, became a fundamental word for his thought beginning in 1936. Finding that this word had many earlier uses prior to its coming to be emphasized by Heidegger, and that it carried other meanings after 1936, would go far towards establishing continuity in Heidegger's thought.

An appropriating event that binds together Being and beings; one that weaves Being, man, things, and world together into an articulated and textured whole that determines" the free spaces, the possibilities of human life, and the historical forms of human Dasein on earth.

In the English translation of Contributions to Philosophy : (From Enowning) the translator < a href="http://webcom.com/paf/hb/hbcontrib.htm">say:

We found a good approximation Ereignis in the word enowning. Above it is the prefix en- in this word that opens the possibility for approximating Ereignis, in so far as this prefix conveys the sense of "enabling," "bringing into condition of," or "welling up of." Thus, in conjunction with owning, this prefix is capable of getting across a sense of an "owning" that is not an "owning of something." We can think this owning as an un-possessive owning, because the prefix en- has this unique capability. In this sense owning does not have an appropriate content.