The date of establishment or date of founding of an institution is the date on which that institution chooses to claim as its starting point. Often the criteria that define a date of establishment or founding are ill-defined—or more specifically, are ill-defined in general, although each institution tends to adopt a rather rigid definition of its own date of establishment.
- Declaration of independence from a now-foreign power, e.g. June 1776 of the United States of America
- Ratification of its constitution
- Signing of a treaty ending a revolutionary war
Yet still more definitions of establishment are possible in the case of each nation state's history and culture.
Likewise, a university may define its date of establishment by:
- The date at which the papers of its incorporation was approved
- The date on which it first opened for the teaching of classes
- If the university derived from a previously-established institution, either the reorganization or the establishment of the parent institution.
Yet still more variations on the definition of the date on which a university was established are possible as considered reasonable by each university's governing body or executive officers.
Ultimately an established date of an institution either is decided upon as an internal matter by that institution or is decided for that institution by a normative higher authority outside that institution. For all institutions falling into a particular type of similar institutions, if the date of establishment is not decided by the same authority using the same criteria variations in the definition of the date of establishment can arise.