The medal is definitely Dutch.
The legend on the obverse can be translated as: William the Third, King of Great Britain and Ireland, Prince of Orange, Count of Nassau.
The Latin phrase Assertori Libertatis on the reverse can be translated as: Thirsty for freedom.
The coat of arms is the king's coat of arms.
I am not sure about the age and origin of the medal. I can only guess and I am not going to do that without further information.