This is another cipher-based challenge I created for my club. The story you uncover is generated from Crusader Kings II. The events of this challenge precede those of the Reverse Engineering challenge.
Members of the club have to search the library for a book on Scottish architecture, but since you can't do that, I am showing you a scan of the relevant page.
This is the journal of Chief Broichan of Buchan.
The day of my marriage to Eadburh, the daughter of the petty king of Kent.
A madman accosted me today. Called me "The Inventor". Claimed to be from both the future and the past. Said something about a book on Scottish architecture. Gave me a note with peculiar scrawls on it, and a map of a country I don't recognise.
My spymaster, a lowborn named Rudri, has provided me with an ingenious technique for obscuring messages. He recommends that I use it for the more sensitive entries of my journal.
A skilled diplomat by name of Fothad has approached me with his services in return for one day pressing his claim on a piece of a large island to the west. isvn ikts sawa itse aoha aerp tnod eess ngre atnh hteh yltn ttbo wsww omeh outd. He will replace my Chancellor, Bishop Bili of St Machar, who has all tcoua gulle rmede hofnk sdura.
I heard Bishop Bili cursing me aloud today. Hopefully this doesn't develop into anything serious. I will name him Master of the Horse to placate him.
isrwrgo nmoraym nbdaate vahkfii aclaiia aeddeot catfhth.
During this evening's council meeting, Marshal Caruorst told us of a local rumour of an artifact hidden not far away from here. I have ordered Caruorst to arrange a search.
Page 425 of The Castellated and Domestic Architecture of Scotland, Vol V
The note that the madman passed to Broichan
The other side has the following messages:
The key is E1E2L3I4. The key opens two locks in two different ways. SEIO PUNZ IRRV DBQS XSCU NGVV PLKU JGJR SGTG CKRH SOGQ ENGY FUTH MGHH MOTF PSSR O LEAF LEAF LEAF LEAF LEAF LEAF LEAF LEAF LEAF LEAF LEAF L