Henri de Valois, in his edition of Ammianus Marcellinus of 1636, gave the title of Anonymus Valesianus to two distinct narrative texts: the first deals with the life of the Emperor Constantine, the second with Theodoric and his kingdom. The first editor already recognized that the two sections have nothing in common except the fact that they were found in the same volume, even if there were later attempts to attribute them to a single author: for this reason Moreau, who edited these texts in the Bibliotheca Teubneriana series, prefers to use the title of Excerpta Valesiana, avoiding the ambiguous title Anonymus Valesianus, which is however commonly used by scholars.

The first part is considered the work of an author who lived before Christianity became the official religion: it makes no mention of Constantine's measures in favour of the Christians, upon which authors later than Eusebius usually focused as reasons for praising Constantine.

As for the Excerpta Valesiana pars posterior, the fact that the discussion focuses on the events of the Ostrogoth reign leads one to assume that the anonymous compiler was of Italian origin, most likely from northern Italy (scholars tend to consider him as active in Ravenna, because of his knowledge of the buildings of the city, and of the similarity of passages in his work to passages of the Liber Pontificalis by Agnellus of Ravenna; others have suggested that the author was from Verona). An apparent change in attitude towards Theodoric is attested from chapter 79 onwards. This lead some scholars, including Moreau, to think that the narrative is the work of two different authors: one wrote the part relating to the first phase of the kingdom of Theodoric; a second one, decidedly hostile to the king, was the author of the section on the subsequent years. However, linguistic (Adams, but cf. Bracke's qualifications) and historical studies (see for example Barnish and Tönnies) have convincingly demonstrated the unity of the text: the strong and sharp change of tone should not be attributed to a different author but to a duality of evaluation.The anonymous compiler wanted to separate clearly the political judgment on the work of the king from his religious attitude, which ultimately lead him to a confrontation with the Senate and Byzantium (Koenig).

The two text that make up the work commonly designated as Anonymus Valesianus are transmitted by a ninth century codex containing historical works. The codex originated from Italy (most likely from Verona) and was stored first in Metz, brought there by Bishop Ratherius, and later in Paris, in the Jesuit Collegium Claromontanum. Before 1764 the codex was divided into two volumes: in a catalog of the library published in that year the two parties are cataloged under the numbers 627 and 680. The index of manuscript n. 680 describes it as a Codex membranaceus in 4° minori (constans foliis 75) saec. IX exaratus. Ibi continentur: I. Isidori Hispalensis historia Gothorum, Vandalorum et Suevorum. II. Anonymus de gestis Constantini Magni. III. Excerpta ex chronicis incertis de rebus Zenonis et Anastasii imperatorum nec non Theoderici regis. IV. Excerpta ex aliis chronicis de rebus Iustiniani et Francorum usque ad Carolum Martellum. The Dutchman Johannes Meermann acquired it at an auction (codex Meermannus 794); after his death, this codex, comprising 75 pages, became part of the library of the British collector Sir Thomas Phillipps (codex Phillippsianus 1885) and is currently preserved in Berlin, in the Phillipps collection at the State Library (Berolinensis). The chronica Theodericiana are transmitted also in the Vatican manuscript Palatino Latino 927, a codex from the twelfth century, written in the monastery of Monte Oliveto near Verona. The Palatine codex carries a mix of historical works, but does not include the Origo Constantini imperatoris. One must conclude that the section on Constantine was not included in the original corpus, but was written to fill in the blank sheets of a quaternion not by the scribe who wrote the other sections of the of corpus, but by another, slightly later, scribe (Cease). As for the relationship between the two codices, Mommsen believed that the Palatine manuscript derived from Berolinensis through a manuscript, now lost, written around 843, since the Palatine includes interpolations present in the Berolinensis. However, where the Palatine manuscript omits passages transmitted in the Berolinensis or, in place of the omitted passages, inserts passages taken from Jordanes, the corrector of the Berolinensis used a cross (+) to mark the discrepancies from the manuscript used for comparison. From this Moreau concludes that the corrector of the Berolinensis was using a book very similar to the one later transcribed by the scribe of the Palatine manuscript. Therefore, the Palatine codex does not derive from a manuscript that was very similar to the Berolinensis, only slightly later, but from a lost book written shortly after 843, which did not contain the places omitted in the Palatine, since the corrector of the Berolinensis used a manuscript from that class of books. So the Berolinensis and C (lost manuscript) derive from lost manuscript A; the Palatine derives from C; C was used by the corrector of manuscript B. [S. Rota; tr. L. Battezzato]