Thank you for your comments.
Just as an example, regarding the narratives of Eusebius and Zosimus, the most important difference between the two historians was that Eusebius was a Bishop since Zosimus was a pagan. When we read Eusebius we'll think that constantine was a saint but when we read Zosimus he claimed that Constantine was a tyrant. Their ideas about Constantine's personality totally different from each other so, I