Providing old myths into new works would help the readers understand why a certain character in the new work choose to pursue a certain action.
The logical reasoning between the myth as a cause that lead to the character's action would force the readers to pay attention to small details of the myth. This will give more depth to the new work.
When Prince Klemens von Metternich wrote "revolutionary spirit could . . . easily hide itself under the veil of patriotism", he most likely meant that: D.) Revolutionaries were trying to hide their true intentions.
What this means is that revolutionaries may hide their true agenda in the name of patriotism.
