The mapping of the past through the construction of a master commemorative narrative also designates its commemorative density, which is the function of what Levi-Strauss calls "the pressure of history." Commemorative density thus indicates the importance that the society attributes to different periods in its past: while some periods enjoy multiple commemorations, others attract little attention, or fall into oblivion. The commemorative density thus ranges from periods or events that are central to the group memory and commemorated in great detail and elaboration to ones that remain unmarked in the master commemorative narrative. Such periods or events that collective memory suppresses become subjects of collective amnesia. Thus, the construction of the master commemorative narrative exposes the dynamics of remembering and forgetting that underlie the construction of any commemorative narrative: by focusing attention on certain aspects of the past, it necessarily covers up others that are deemed irrelevant or disruptive to the flow of the narrative and ideological message. Bernard Lewis points out the phenomenon of recovering a forgotten past. Yet it is no less important to note that such a recovery may lead to the covering up of other aspects of the past. Remembering and forgetting are thus closely interlinked in the construction of collective memory.

Zerubavel, Y. (1997). Recovered Roots: Collective Memory and the Making of Israeli National Tradition. University of Chicago Press, p. 8.