- Genius Bonus: Cadfael's conflicts with Prior Robert and other conservative monks are a microcosm of the intellectual conflict then raging in Western Europe between neo-Aristotelianism and Augustinianism. Neo-Aristotelianism originated in the Middle East, where Cadfael spent his youth.
- Moral Event Horizon: Corbière in Saint Peter's Fair crosses it when he implies that he'll rape Emma—or at least molest her—if she doesn't give up the MacGuffin.
- This is how Hugh Beringar, a loyal official, views Bourchier, alias Cuthred betraying his liege in her darkest hour.
- Tear Jerker: In The Leper of St. Giles, the old man Lazarus chooses to go quietly on his way after giving aid to, and setting matters right for, Iveta de Massard and Joscelin Lucy. He doesn't even linger long enough for them to thank him. Only Cadfael knows the truth—that he is Guimar de Massard, Iveta's grandfather, reported as having died of battle wounds in the Holy Land. He is no longer actively afflicted with leprosy and is no danger to anyone, but the illness has left him grotesquely disfigured, and he is content to remain dead in the eyes of the world now that he knows his granddaughter will be safe and happy.
YMMV / Brother Cadfael