Welcome to the Western Norway version of "The Jasmer Challenge". You must have logged at least one cache that was placed in every month back to the start of Geocaching (May 2000).
In order to log this cache, you need to provide the GC code of a cache that was placed in each month for all of 2000 and 2001 in your log entry. Of course, you have to have a find for caches placed in all other months (up to and including the last full month) as well, but those tend to be easier to come by and don't require as much verification.
When you qualify, I suggest that you save a screenshot of your profile statistics or the result of the challenge checker. Feel free to post a note, even though it will take some time before you actually get around to sign the log.
In other words, once you've qualified once, you can log this cache :)

Oldies
This challenge will require you to visit a lot of old caches. A lot of great caches. I guarantee you that you will have a lot of fun. And you will make lots of great memories!
This challenge is definitely the best challenge we've ever worked on ourselves!
The oldest active geocache in the world is currently GC30 Mingo. You do not need to find that exact cache to qualify for this challenge, but it will help you get the first month you need!
If for some reason any month will be completely unavailable to find, that month will be excluded from this challenge. But as of now, all months are there, ready to be found by you.