I have written several times about the need to locate multiple annotated copies of auction catalogues, because the annotations in any one copy cannot be trusted as reliable. And I have written (e.g. here) about the need to distinguish between the date on which a manuscript was sold and the date on which the auction commenced, because these are often not the same. In looking at the famous 1856 sale at Christie's of the collection of the poet Samuel Rogers (mentioned e.g. here), both these principles are exemplified, as will be discussed today and in next weekend's post.