Copying a manuscript was painstaking labour and could take a single, or a few scribes a couple of weeks to make a plain working copy of a text to several months or years to produce illuminated manuscripts adorned with decorative initials and intricate illustrations. Upon completion of their labour some scribes signed their name and added a closing remark:

‘Sy þeos gesetnys þus her geendod. God helpe minum handum’ : ‘Thus, let this composition be ended here. God help my hand’. British Library, Cotton Tiberius B.v, fol. 28v

Naturally, copying long works by hand for hours at a time and even by candlelight meant few were free from error. Misspellings, missing words and skipped lines could occur and scribes were even instructed to reproduce any mistakes they spotted in the text they were copying from, with the aim of creating a perfect facsimile of the existing work. Errors in language, grammar and syntax could also pass unnoticed depending on the knowledge and training of the scribe. Some scribes still attempted to make textual corrections by scraping the ink off the parchment with a knife or simply crossing through or overwriting the error. Even if a text was reproduced perfectly the copying process could leave its mark in physical defects like blotches, ink marks, fingerprints and candle wax stains.

Over the 15th and 16th centuries the creation and dissemination of texts began to shift from the scriptorium to the printing house, and from a work of singular labour to mass production. Where before one person might have cast their eyes over a manuscript a new process of collaboration existed between author, compositor/typesetter, illustrator, printer and censor providing multiple opportunities to identify, and also to introduce, errors. Some historical typesetting mistakes particularly those found in Bibles have gained notoriety such as the ‘Wicked Bible’ where the seventh commandment reads: ‘Thou shalt commit adultery’. King Charles I ordered all copies of the Bible to be burnt but around 11 are known to survive. Apart from simple typos the printing process introduced errors which wouldn’t have occurred in manuscript production like missing sheets, text printed upside down or printed on only one side of the sheet, and pages printed out of sequence. Similarly, unlike hand drawn illustrations the rigidity of typesetting meant scientific and mathematical works which included figures, formulas and graphs could be difficult to execute perfectly. If the bookseller or binder noticed faults quickly there was a chance to alert the printers but the speed at which books were printed and distributed often meant it was impossible to retrospectively correct all the copies.

Unlike scribes who would check a manuscript upon completion and correct mistakes by hand the printing process meant proofreading needed to occur before the text was printed and could be carried out by the author, a hired proofreader or the printing house. There were various methods to make small corrections after printing, like pasting a slip of paper over the text, but larger errors might involve cancelling and reprinting a page, inserting a manuscript page supplying the missing text, or starting a new print run or edition. The most common method employed post publication was to include a ‘Corrigenda’ or ‘Errata’ leaf which listed all of the identified errors, usually with an apologetic preface to the reader inviting them to ‘amend with thy pen’.  They were still in use in the 20th century in the form of correction slips pasted into books. Mistakes were so common that some authors used the errata statement to express frustration with the printer and likewise printers might attribute the absence of the author at the press for the errors; the inevitability of errata even inspired a literary form of satire like John Taylor’s verse poem ‘Errata, or Faults to the reader’. However the expectations of contemporary readers was different from today and it was accepted that the reader, owner or librarian might need to alter the text of their books according to the errata list. For centuries printed works would continue to require mediation by hand and this active engagement is evidenced by the marks, scribbles, doodles, glosses and comments we find on the pages.