Access to Marketo History Table?

You could ask Support.

What they mean is that Marketo tracks the changes in each field as well as the log for each lead. This is not really accessible to you except via the Data Value Was Changed type filters.

If Birst says it can access the lead log or the main table, then they probably can via the API.

Update on this topic.  There is a history table in MKTO and Birst can access the history table using their standard MKTO connector.  The challenge is that there are multiple separate tables where you can get history data.  That makes it challenging to get a single snapshot of different possible fields at a particular moment in time.

In our case, we're trying to capture snapshots of custom fields that contain tracking information whenever a program success occurs.  What we found is the program success data is one table and the fields with the tracking data is in a separate table and there's no easy way to associate the two sets of data to each other.  For example, when someone registers for a webinar, the MKTO form captures the tracking data in 5 fields.  The name of the webinar program and the record that a Lead registered for the webinar is in one table.  The data showing the change in the values of the 5 fields is in a separate table.  So there's no easy way to associate the two sets of data to each other.  We have a Birst consultant working in this and he's put several man weeks into the effort and hasn't come up with a solution.

So if you're thinking about using any BI tool to try to pull data from MKTO history tables, figuring out how to associate data stored in separate tables is a significant challenge.