Genius?

So what isn't a game?

Genius continues to fascinate me.  What it might mean, or if it has any meaning at all beyond mastery.  Is genius simply an honorific, or does it have a real descriptive value? 

What I like about the term is its “guiding spirit” aspect.  “She sang beyond the genius of the sea” kind of genius. 

From Wikipedia (because why not?):

In ancient Rome, the genius (plural genii) was the guiding spirit or tutelary deity of a person, family (gens), or place (genius loci).  The noun is related to the Latin verb gigno, genui, genitus, "to bring into being, create, produce." Because the achievements of exceptional individuals seemed to indicate the presence of a particularly powerful genius, by the time of Augustus the word began to acquire its secondary meaning of "inspiration, talent."

And then, to kind of blend talent back to the Roman, I think of a genius as a person who functions as a guiding spirit of an age, and that gives me a category within which I can place individuals.  Not just emblematic of a time, but guides to and of a time. 

But what of the unrecognized genius?  Could that person still be a genius?  Or does genius need an observer, a time to guide?  A writer such as Emily Dickinson would be a good example.  She isn’t a genius in 1880, but she is in 1980.