I have the following in my init.el
file:
(setq org-agenda-span 36)
(setq org-agenda-start-on-weekday 1)
(setq european-calendar-style t)
However, diary blocks are still interpreted as month first, then day, then year:
*** Urlaub!
<%%(diary-block 02 11 2018 10 11 2018)>
is interpreted as "February, 11th, 2018 - October, 11th, 2018".
My Emacs version is: GNU Emacs 25.2.2 (x86_64-pc-linux-gnu, GTK+ Version 3.22.21) of 2017-09-22, modified by Debian
My Org-Mode version is: Org-mode version 8.2.10 (release_8.2.10 @ /usr/share/emacs/25.2/lisp/org/)
I remember, that I had it working correctly before. Maybe the issue arose when I updated to Emacs 25.