You may or mat not have thought about it, but I have a category named "translations". As you might imagine, it contains things of a translated nature, written by the very translator that writes these very words.
I sure wrote a lot of things back in the days. As in, thousands of them.
Translating these things poses a quite interesting set of challenges. Not least among these are those relating to genre and context - how do you go about translating things that are part political pamphlets, part engaging in a very particular community of discourse, and part exploratory writings whose only motivation were the author's pleasure in spending time with a particular thought?
Needless to say, there are certain things lost in translations.
Another difficulty lies in the intertextual dimension. One text talks to, relies on and presumes familiarity with another, which in turn does the very same things to an other, and so on in a great chain of textual being. Which, in practical terms, means that you can't really just translate the one text and be done with it - you have to dig back in time to the one text that stands (or can be made to stand) on its own contextual feat (or feet), and then move forward from there. Until you reach the point where enough inter- has been suffixed to the text you initially wanted to translate.
There is an aspect of archeology and genealogy at work here.
Yet another difficulty lies in the notion of fidelity. Time has passed between the writing and the translating, after all. New things have been learned, new experiences had, and new patterns of writing adopted. The translator is (hopefully) always wiser than the author, and all those mistakes that were made at the time of writing are visible with the predictive clarity of hindsight. And there is the ever present temptation to learn from the past, correct the mistakes and improve upon the present.
As the author, I do profess to claim some authority of/on the text at hand. Changes were made. Fidelity be damned.
All this applies. And that without the added complexity of having to take into account the triple hermeneutics of translating something that is not of one's own writing.
The question is, indeed - how do you translate authority?