Columbia subject headings:
Harvard subject headings:
Enlightenment
Frederick II, King of Prussia, 1712-1786.
Voltaire, 1694-1778--Criticism and interpretation.
Voltaire, 1694-1778--Influence.
Princeton subject headings:
Enlightenment.
Frederick II, King of Prussia, 1712-1786--Friends and associates.
Voltaire, 1694-1778--Friends and associates.