National myth
A national myth is an inspiring, or patriotic story or anecdote that serves as a national symbol of a country, and re-affirms a country's "national values."A national myth is not necessarily a myth in the sense that it is false, but may instead be a simply over-dramatized historical story in which certain details are ommitted or changed in order to make it more inspiring.
For example, the American Revolution is the source of many national myths, such as the legendary ride of Paul Revere and the Boston Tea Party.
In France, the execution of King Louis is likewise a national myth which plays up the triumph of the common people over the out-of-touch aristocracy, personified by Queen Antoinette's statement (actually a misquote) of "Let them eat cake."