I felt instantly guilty ... it was a tap upon my shoulder. The sort of tap which is likely to be followed by invitations to comealongame, and Not To Make Any Trouble, together with the chink of handcuffs.
I was about to start bleating about how I wasn't guilty; that it was the other bloke what did it, when I recollected that, in the archives of the City of London, my interlocutor was unlikely to be PC Plod or Inspector Knacker or even Dame Cressida, er, Dick.
As one enters those archives, one writes in a register the subject of one's researches. So I had written "Sir John Percival". The aimiable and erudite custodian had seen this, and had some news for me.
In the City Church of S Mary Woolnoth, there had once been a manuscript, beautifully scribed and on display, in which Sir John Percival, Master of the Worshipful Company of Merchant Taylors, sometime Lord Mayor of London, detailed his benefactions, together with the provisions made to endow Masses (with chantries) for his soul. Percival was one of the closest circle of intimates of the Welsh Intruder, Tudor, known to History as Henry VII. Percival was one of the notable men of the new regime.
But his desire for the Mayorality had attracted so little support among the other livery companies that one of Tudor's heaviest enforcers, Bishop Savage of London, had needed to explain realpolitik to the City Fathers.
As everybody knows, the Great Fire of London was to destroy pretty well every single one of the old churches, together with every tiny bit of their contents. Usefully, earlier writers had recorded Sir John's text, together with the information of its certain demise in the all-consuming flames.
Except that, um, it hadn't demised. After Wren, vir nonnunquam laboriosus, had rebuilt all those churches in the style which some snooty people refer to as Impure English Baroque, the ms had (wisely) taken refuge in a ... doubtlessly 'Wren' ... cupboard.
Where it had recently been noticed, just in time for my researches!
Y'know, I do rather wonder whether the Great Fire was as determinedly catholic in its destructive embrace as we used to believe. Did Old S Paul's, with its sleek new Inigo Jones facade, really have to be dynamited away?