I am writing to post some information on the origins of the ages in myth. This may have been posted in the past 4 years if so forgive me, I thought it was worth mentioning regardless.
I picked up a book on medieval literature, and happened to look at the Tutonic works. I came across a story called Snorri Sturluson and by chance turned to a page that happened to list this passage:
Brothers Shall Strive and slaughter each other;
Own sisters' children shall sin together;
Ill days among men, many a whoredom:
An axe-age, a sword-age, shields shall be cloven
A wind-age, a wolf-age, ere the world totters.
If I remember, all four of those ages mentioned above exist in the myth universe, so I think its a good bet this is where they came from.
Cheers