Showing a decline in Date/Month based on previous cell

In Cell A1 I am using the current date function =NOW()
I am formatting it to show JANUARY-2014 (mmmm-yyyy)

In Cell A2,A3,A4 etc, I want to show the previous cell minus one month, basically have it show A2 to show, DECEMBER-2013, A3 to show NOVEMBER-2013 etc.

I found that something simple as =A1-1 would not work

Thanks for any help.

Nick