She traced over two centuries of English letter writers, beginning with Latin formularies, and pointing out the social significance of the changes in epistolary models over the period.
[8] For instance, the popularity of Nicholas Breton's A Poste with a Packet of Madde Letters (1602), she showed, sparked a trend for pithy and entertaining guides to correspondence.
[9] However, other scholars criticised the work for not establishing clearly enough what the golden standard was for letters: a simple style (as espoused by Sir Thomas Browne or Hannah Woolley) or affected (as evidenced in Cupids Messenger (1672)).
There had been five manuscripts found in 1907 but only one of these, arbitrarily chosen by Albert Feuillerat, was printed in 1926, with no effort to establish concordance between the copies.
By the time Robertson began her work, nine manuscripts were known, and she divided these into four groups, representing four revisions by Sidney, before his drastic rewrite into the New Arcadia.