In The History of the Decline and Fall of the Roman Empire, Gibbon mentions that Roman magistrates under Constantinus the Great had such titles as; your Sincerity, your Gravity, your Excellency, your Eminence, your sublime and wonderful Magnitude, your illustrious and magnificent Highness (Ch. 27 in Volume 2). I have been trying to find them in the original language with no avail. I am not even sure if they were originally in Latin or Greek.
A note in Decline and Fall suggests Gibbon took those "wonderful" titles from Notitia Dignitatum. I have consulted that too, but cannot seem to find anything related.
I hope someone could help me. Thanks in advance.