This coin is from the mid 1600's. Here is a picture:
http://www.sprezzatura.it/Arte/jeton_bouclier2.jpg
The other side of the coin has '
Comitia Burgundiae', and French journal
* identifies Burgundy as the subject of the slogan.
[Burgundy] stood up against a few; it has fallen to many.
(I know too little of French history to explain the circumstances.)
There is a disc shape on the coin that the coin books identify as a shield threatened by arrows.
However, there are quite a few internet sites that identify the image as a flying saucer, and consider it possible evidence that the earth was visited by beings from outer space in the 17th century. This reading influences their translations of the Latin, which are usually inaccurate.
The in the coin discussed in this thread, which has the same design, has aroused the same sort of speculation:
opportunus adest
*Source:
Bulletin, Volumes 1-6 By Société d'études d'Avallon