Silences enter the process of historical production at four crucial moments: the moment of fact creation (the making of sources); the moment of fact assembly (the making of archives); the moment of fact retrieval (the making of narratives); and the moment of retrospective significance (the making of history in the final instance).
Trouillot, Michel-Rolph. Silencing the past: power and the production of history. Boston, Massachusetts: Beacon Press, 1997.The process of identifying materials offered to an archives that have sufficient value to be accessioned.