Note: Archiving your calendar puts these entries into a pst file on your local computer, so you cannot access these archived entries from another machine.
1. Go to File > Archive
2. Select the second option Archive this folder and all subfolders select Calendar from the list
3. Choose a date from Archive Items older than, then click on Browse under Archive to select where to archive the entries to.
4. Click OK when you are done
In Calendar view, you can now see Calendar in Archive folders under "My Calendars" so you can now view these archived entries by selecting the check box.