The purpose of this thesis is to assess the extent to which the singular readings of a manuscript reveal the tendencies of the scribe who wrote its text by examining three related Greek manuscripts from the sixth century. The three manuscripts are all luxury copies of the Gospels' purple codices, so named because they are written in silver and gold ink on parchment that has been dyed purple. The manuscripts, Codex Purpureus Petropolitanus (N 022), Codex Sinopensis (O 023) and Codex Rossanensis (Σ 042), were all copied in the sixth century from a common exemplar. Chapter One introduces the three manuscripts. Chapter Two provides a history of research on scribal habits and singular readings, and it describes the method used in this thesis to determine both the validity of the singular readings method and the actual scribal habits of 022, 023 and 042. Chapter Three provides a preliminary assessment of each scribe by comparing scribal features in the passages extant in all three manuscripts. Chapters Four, Five and Six assess the scribal habits of 022, 023 and 042, respectively. In these chapters, perceived scribal habits are measured by a modified singular readings method to replicate the situation for each manuscript if it had no extant close relatives' the situation for most early manuscripts. Actual scribal habits are then determined by the places the scribe changed the text of the exemplar. Chapter Seven offers some concluding thoughts about the scribes, their exemplar and the use of singular readings to determine scribal habits. Appendix One presents for the first time an edition of the reconstructed text of the exemplar of 022, 023 and 042, where at least two of the three manuscripts are extant. Appendices Two, Three and Four are full transcriptions of the Gospel of Matthew in 022, 023 and 042, respectively. Appendix Five provides information on singular readings and corrections in 042 where it alone is extant of the three manuscripts. Appendix Six describes the codicological structures of the three manuscripts. Appendix Seven is a transcription and brief discussion of 080, a fragmentary of a purple codex dating to the sixth century. Finally, both 022 and 042 contain a series of secondary corrections made against a second exemplar, and Appendix Eight argues that the scribe of 042 was responsible for these corrections in both manuscripts.