“ A culture must hide its hands in the arm of their clothing as a sign of respect and peace. When approaching somebody you show them respect by crossing your arms and hiding the hands in the shirt sleeves. Nobody worries about hidden knives and such, it is the threat of magic that this custom was created to prevent.”
“ A Deity of some sort has unleashed a plague of bookworms or something like that in the area. Almost all spellbooks are destroyed, along with bardic and historical books.”