Setting a date to first activity in Activity history

[Anonymous]

Is there a way to set a Marketo/SFDC date field to the first time something happened.  To be specific, I would like to retroactively examine each leads historical activity and set an opt-in date for the first time they opened or clicked an e-mail.  

The difficutly here is that I don't want to set wether or not they have opened an e-mail, but the date where they first opened an e-mail.  Of source many users have opened several different e-mails, and the requirement here is to only pick up the date for the first opened e-mail.  

[Kim_Allen]

Hey Scott,

You can make custom fields that time stamp certain actions. I believe there's lots of examples of this around the community, but here's the first thread I stumbled on, just to get you started:

https://community.marketo.com/MarketoDiscussionDetail?id=90650000000PQVyAAO

And you just won't want to let the system to update those fields so it keeps the time stamp for the first action.

[Anonymous]

That is a great solution going forward.  What I am looking for is a way to retroactivaely set the first opt in date on lead records.  

[Anonymous]

I'm trying to do the same thing. Did you get anywhere with this?