It's not exactly Dan Brown material, but there's now one less unsolved church mystery in the world:
An Anglican priest has unlocked the 270-year-old secrets of Charles Wesley's coded diary, throwing light on the turbulent relationship that he had with his brother John in the early years of the Methodist movement they founded.
[lab]oratory has a great post talking about Wesley's diary, ciphers, and cryptography. (I also just realized that [lab]oratory's header graphic is a screenshot from Ultima 6. You, sir, are awesome.)
The Times Online article makes a big deal about the juicy and mildly scandalous personal tidbits that the diary reveals about Wesley's life: he was apparently involved in a rather petty-sounding dispute with his brother about the latter's proposed marriage. Details like these might be used to discredit historical figures (the article describes Wesley as a "depressive" person), but I find these little revelations both interesting and helpful in understanding Wesley as a Christian.
Growing up, I read through a reasonably large chunk of Christian writing from throughout church history, and reading the "greatest hits" of noteworthy writers like Augustine, Calvin, Luther, and Whitefield in isolation can create the false impression that these writers are... well, more perfect than they really were. When I got into college and learned that some of these famous Christians held unusual beliefs or were decidedly quirky individuals, I was taken aback—but that realization humanized them and helped me distinguish better between their ideas and the Scriptural teachings they were trying to elucidate.
How about you? Have you ever been disillusioned to find that a church history "hero" was a fallible human being after all?