Like another recent question of mine, this question was prompted by my reading the German translation of Lord Of The Rings. In the context of a company of soldiers, a German word meaning men was used, but instead of Männern, which it normally would have been in the context, it was Mannen.
Is this another archaism, or is it something which is still used in a military context, as when the men are considered merely as a measure of the size of the unit, rather than as individual people?
IANA native German speaker but I seem to remember having seen Mannen used as a dative plural in certain archaic texts. Did you see this in dative case? Can you provide the excerpt?
With extensive Googling, the only reference I could find to this was on pages talking about Plattdeutsch, which is apparently a Northern German dialect. Could it be that the translator was trying to convey a sense of ‘rurality’, so chose a word that most Germans would recognize as peasant-like ?
“Mannen” would be used - as you pointed out in a slightly archaic way - when describing somebody and his underlings, like a leader and his army or for example “Robin Hood und seine Mannen”.