Chronicles of the East Kingdom
The Chronicles of the East Kingdom is a single page document discovered among the files of the East Kingdom Historian. It purports to describe the founding and first year or so of the East.
From the reference "...El of the Two Knives as Chancellor of the Exchequer, a post he has held under every monarch since." we can place the time of its writing to before October 1972, when Wilhelm of Bothnia took over the job of Exchequer.