So I'm playing CK2 and a crusade was called against my (Zoroastrian) religion in France. I joined up to help my fellow member of the faith, but when the Crusade started, I was unable to actually join the war and help them. As far as I know, I have no truces with any Catholics. I click the "offer to join war" button, but there's no option to join the crusade. What could have caused this? Is there any way to fix it? I don't want my religion's moral authority to tank because of this! Any help would be greatly appreciated!