Historical significance is a historiographical key concept that explores and seeks to explain the selection of particular social and cultural past events for remembrance by human societies. This element of selection involved in both ascribing and analyzing historical significance is one factor in making the discipline of history distinct from the past. Historians consider knowledge of dates and events within and between specific historical periods the primary content of history, also known as "first-order knowledge" or substantive concepts. In contrast, historical significance is an example of a subject specific secondary key concept or "second-order knowledge" also known as a meta-concept, or disciplinary concept, which is typically used to help organize knowledge within a subject area, frame suitable areas of inquiry, provide the framework upon which substantive knowledge can be built, and map learner progression within a subject discipline. Specifically with regards to historical significance, the way dates and events are chosen and ascribed relative significance is not fixed and can change over time according to which criteria were used to form the judgement of significance as well as how those criteria were chosen themselves in the first place. This aspect to significance has been described as:
Historical significance is often regarded as involving judging why a particular person or event is remembered and why another is not, it is this aspect of reasoned and evaluative judgement about historical significance that makes history writing differ from being simply a record of past events.
