They definitely had motives beyond just "neutrally" analysing the past. I can link some earlier answers about this. Firstly in this thread u/Valkine explains the difference between chronicles and annals, and their similarities/differences to modern works of history. The same user has also written about bias in Froissart's Chronicles, and u/alricofgar has discussed the same phenomenon in Early English accounts of vikings. Finally, quite recently u/J-Force, u/qed1 and some others had a discussion about how mediaeval authors perceived and portrayed history on a larger scale