What literary term does all the knights of St. Louis describe?

The phrase "all the knights of St. Louis" can be understood as a reference to metonymy, where a closely related term is substituted for an object or idea. In this case, it represents the values, virtues, or ideals associated with the knights or the historical figure of St. Louis, rather than the knights themselves. This literary term effectively conveys a deeper meaning by invoking the cultural and historical significance of the knights.