To search your Gmail archives for a message or discussion that is older than a certain time, you just need to perform a few simple steps, or launch an advanced search.
Steps

Step 1. Go to Gmail's search bar
If you've opened Gmail in a web browser, the search bar is at the top of the screen. If you are using the Gmail mobile app, you need to tap the magnifying glass icon to access the search bar.

Step 2. Find a post after a specific date
To do this search, type after: YYYY / MM / DD in the search bar by replacing these letters with the date from which you want to search. For example, to search for emails sent after March 29, 2015, type after: 2015/03/29.
- You can also use the command newer in the place of after.

Step 3. Look for an email older than a certain date
You probably guessed it already, the command to do this search is before: YYYY / MM / DD. You can also use older in the place of before if you want it.

Step 4. Use both terms to refine the search
You can use both terms above in the same search. For example, research after: 2015/03/29 before: 2015/04/05 will display all emails sent during the period from March 29, 2015 to April 5, 2015.

Step 5. Use relative terms
To search for recent mails, you don't need to enter an exact date. Instead, use the commands older_than Where newer_than.
- older_than: 3d = emails older than 3 days
- newer_than: 2m = messages less than two months old
- older_than: 12d newer_than: 1y = mails more than 12 days old and less than a year old.

Step 6. Add additional terms
You can add regular terms to the same search, as well as other advanced search terms. Below are some examples.
- The research after: 2015/01/01 before: 2015/31/12 escalade will display all messages from 2015 that include the word escalation.
- The research newer_than: 5d has: attachment will display the list of emails from the last 5 days with attachments.
- The research before: 2008/04/30 from: Jeanne danse will display the list of emails prior to April 30, 2008, coming from Jeanne, and containing the word dance.