How to view messages for a longer period?

In all e-mail folders I see messages for the last 365 days. How to view messages for a longer period? I have checked the archive folder, but all messages not older than 365 days.

idea 1: automatic Archiving of eM-Client active?
idea 2: IMAP-Accounts? Perhaps the eMail-Provider deletes Messages after that period of time?

Fritz

No, POP 3 account.
Automatic Archiving is on. How do I view messages moved to the archive?

OK, as far as I understand, we did find the reason why those messages “disappear” - right?

New question is: How to access those archived messages.
Sorry, no Idea since I disabled this function…

Fritz

It seems that is what I need.
How I can get access to archived messages?

If you have archive on and some data was moved then the archive folder wiil be visible just under your normal account folder on the left of the screen (version 6 or 7)
If your archive is too long maybe your email service is deleting them before the archive even gets to them.

Archive in version 7
Menu
Tools
Settings
Mail
Auto Archive 

For a test look at your mail and pick an email (oldest)  and set autoarchive with enough days to select that old one and see if it moves it to the archive folder.
Note much better to use imap rather than pop
Hope this helps