The concise history of Rome, covering the 700 years from Romulus until Augustus and composed by an author with the cognomen Florus, is ranked since the Renaissance among the most often printed and most widely read ancient Latin prose works. But whereas this small work was until now commonly supposed to have been written by a “L. Annaeus” oder “P. Annius” Florus during the age of the emperor Trajan (or even later), the present article — based on four essays I have published already more than 20 years ago — demonstrates that almost the entire work was originally composed by a contemporary of Augustus, most likely by the same Iulius Florus to whom Horace addressed two famous letters (I 3 and II 2). We must, indeed, distinguish between two different versions of this work, namely on the one hand the genuine text edited by Iulius Florus, whose name appears as the author in the very important Codex Bambergensis (9th century), immediately after the consecration of the deceased Augustus (17 Sept. 14), and on the other hand a second edition prepared by an anonymous redactor in the era of Trajan (98–117), which was considered a revival of the Golden Age of Augustus; in addition, some further editions appeared later in the second century. All these new editions of Iulius Florus’s work contain just two crucial differences from his original text, namely two short interpolations in Iulius Florus’s preface: the short colon ut postea velut consenuerit, inserted into § 4, and the last sentence (§ 8), added to the original preface. Both interpolations, however, stand in marked contrast to the entire context of Florus’s composition. The main purpose of my article is, therefore, a reconstruction of the original form of Iulius Florus’s historical work, which contained not four or two books (as it is now generally assumed), but only one book, presented as a brevis tabella or breviarium of Roman history.