Posted:
In the book "The empire of the great mogol" by Joannes De Laet, who lived during the period of emperor jahangir/salim.
writes that ,prince salim was born to a concubine of akbar.
on pg no. 147 and 148 under the heading ..(foundation of fatehpur sikri)
here is link to the book and that page
https://archive.org/stream/empireofthegreat035526mbp#page/n165