Explanation: Historians used to be extremely reluctant, due to lingering Victorian-era mores, to acknowledge GSMs in history. Nowadays the problem is much reduced, and historians are generally more open to acknowledging the GSM identity or possible identity of historical figures.
The Roman Emperor Elagabalus is now generally considered, if a third of the stories repeated about them by contemporary histories are true (and while Elagabalus was unpopular, the stories are remarkably specific accusations to level against someone), to have been trans or NB.