I met some odd usage of preposition "for". I guess it's old style, or high style. I give examples for better understanding:
About this time legend among the Hobbits first becomes history with a reckoning of years. For it was in the one thousand six hundred and first year of the Third Age that the Fallohide brothers Marcho and Blanco, set out from Bree.
J.R.R. Tolkien
But the Hobbits may have learned it direct from the Elves, the teachers of Men in their youth. For the Elves of the High Kindred had not yet forsaken Middle-earth...
J.R.R. Tolkien
In the study of logic, we do not so much look at these kinds of reasoning: instead, logic concerns itself with reasons for believing something instead of something else. For beliefs are special.
Routledge. Logic. An Introduction.
It would be great, if someone explain me how to understand the authors in these cases. Thank you.