Without doubt, the finest example of illumination to be found amongst those early manuscripts held by the State Library of Victoria is the Scriptores Historiae Augustae — one would not, in fact, be hard pressed to mount a case for its being considered the most beautiful item in the Library's collection.

The manuscript, produced in Florence in 1479 (or 1478 by the Florentine calender), bears the Medici arms on its title page, thereby testifying to its having been produced for that family; the date further indicates that the family member who commissioned it could be none other than Lorenzo the Magnificent.

The text of the manuscript, in Latin, consists of three separate works: the Scriptores Historiae Augustae, a collection of lives of Roman emperors from Hadrian to Numerian (A.D. 117–284), probably written for the Emperor Julian the Apostate in 362–363; Breviarium ab Urbe Condita, a summary of Roman history by Eutropuis (c.370) which was later translated into Greek by Paeanius (c.380) and then back again into Latin by Paul the Deacon (c.739–799); and Paul the Deacon's Historia Romana, a continuation of Eutropius’ history.

The illumination of the manuscript includes eighty-one historiated initials containing portraits of Roman Imperial figures which precede each of the chapters. The first portrait, derived from a coin, is that of the Emperor Hadrian; the remaining portraits, however, do not correspond to known Roman images drawn from coins or statues, although three of the depictions do, in fact, emulate coins. Like the Florentine script and the decoration used throughout the manuscript, these portraits are of the highest quality, being set, in most cases, against a background of highly patterned burnished gold.

The history of ownership of the manuscript is reasonably well documented. It is believed to have remained in the possession of a member of the Medici family in the sixteenth century. It next surfaces in England after the Napoleonic Wars in the possession of Abate L. Celotti who, in 1816, had acquired it as part of the collection of Don Tommaso de Lucca. Things then speed up dramatically; Celotti sold it to Sotheby's on 25 July 1825; Sotheby's, in turn, sold it to Payne and Foss. In 1826, the manuscript was acquired by Sir Thomas Phillipps, whose signature appears on the fly-leaf, along with his Middle Hill insignia — a stencilled lion rampant. Phillipps is considered by many to have been the world's greatest book collector and boasts an interesting Australian connection in his having published at his Middle Hill Press in 1856 a chromolithographed facsimile from Nicolas Vallard's 1547 atlas, then in his possession, entiled The first map of Australia. Upon Phillipps’ death in 1872, the manuscript remained in the possession of Mr. Fitzroy Fenwick, heir and grandson to Phillipps, until it was eventually purchased as part of a bulk lot by W. H. Robinson Ltd., booksellers in Pall Mall. The manuscript came to the State Library of Victoria in 1947, having been purchased directly from Robinson.