Another question with which the textual critic of modern authors must be prepared to deal is the relative importance of different editions, each of which may have a prima facie claim to be considered authentic. Thus Shakespearean criticism must decide between the evidence of the first folio and the quartos: the critic of Shelley's poems must consider what weight is to be attached to the readings in the posthumous edition by Mrs Shelley, and in unpublished transcripts of various poems. Where there is great or complicated divergence between the editions, as in the case of Marlowe's Faustus, the production of a resultant text which may be relied upon to represent the ultimate intention of the author is well-nigh impossible.
This last class of documents exists in England mainly in the form of transcripts from the originals in foreign archives, which have been made for the purpose of the Venetian and Spanish Calendars of state papers.
The Venetian Calendar had by 1909 been carried well into the I7th century; the Spanish (which includes transcripts from the Habsburg archives at Vienna, Brussels and Simancas) covered only the reigns of Henry VII.
The extant remains of these laws are manuscript transcripts from earlier copies made on vellum from the 8th to the 13th century, now preserved with other Gaelic manuscripts in Trinity College and the Royal Irish Academy, Dublin, the British Museum, Oxford University, some private collections and several libraries on the continent of Europe.