The collection can be divided broadly into three sections according to the nature of its contents: cc. I–V, containing conciliar canons from the major fourth-century eastern and African councils; cc. VI–LVII, being a long series of documents (mostly letters) pertaining to doctrinal disputes that arose from the teachings of
Pelagius and
Celestius and also of
Nestorius and
Eutyches―at the centre of which series is a dossier (c. XXV) of material pertaining to the council of Chalcedon in 451—and cc. LVIII–XCVIII, a collection of dogmatic and disciplinary letters written by
Pope Leo I, many of which (most notably Leo's
Tomus) were directed to eastern figures in Leo's contests with the
Eutychian and
Monophysite heresies. The entire collection, with its focus on Chalcedon and the letters of Leo, is quite obviously meant as a manifesto against the
Acacian schism, in which eastern Bishops led by
Acacius, patriarch of Constantinople, challenged the decisions of the council of Chalcedon and the
Christology set down in Pope Leo's
Tomus. The compiler's principal of selection thus seems to have been any and all documents that support doctrinal unity in general and Leonine Christology in particular. The compiler of the
Quesnelliana has avoided inclusion of doubtful or spurious documents, like the so-called
Symmachean forgeries and the
Decretum Gelasianum de libris recipiendis. But this would seem to be the extent of discrimination exercised in the compilation of the
Quesnelliana. Previous scholars have in fact spoken rather disparagingly of the overall organization of the
Quesnelliana, characterizing it as something of a hotchpotch, a patchwork of several older and smaller collections that were available to the compiler. Despite its organizational flaws, however, the
Quesnelliana enjoyed some popularity in the Gallic church during the eighth century, and much of the ninth as well, until it was superseded by the more comprehensive historical collections (notably the
Collectio canonum Dionysio-Hadriana and
pseudo-Isidorian collections) that arose in the later
Carolingian period. Of the large chronological canon collections to have come out of the early
Middle Ages, the
Quesnelliana is perhaps the earliest and, after the
Collectio canonum Dionysiana and
Collectio canonum Hispana, probably the most influential. It contains Latin translations of the eastern councils that are (with the exception of the council of Chalcedon) taken from a now lost collection of Latin canons made ca. 420. This earliest Latin collection of fourth- and fifth-century conciliar canons was previously known to scholars as either the
versio Isidori or the
Collectio Maasseniana, but is today referred to as the
Corpus canonum Africano-Romanum. The
Africano-Romanum collection/translation predates the competing fifth-century Latin translation that
Dionysius Exiguus referred to as the
prisca (upon which the
Collectio canonum Sanblasiana is based). Both the
Africano-Romanum and
prisca translations were largely superseded by the arrival, shortly after 500, of the superior translations of the several collections of Dionysius Exiguus. The exact date of the
Quesnelliana’s creation is not yet established, but it could not have been earlier than the appearance of the
Africano-Romanum in the first half of the fifth century; nor could it have been earlier than the date of the
Quesnelliana’s most recent document,
Pope Gelasius I’s
Generale decretum (not to be confused with the spurious
Decretum Gelasianum), which dates to 494. Most historians have accepted the Ballerini brothers’ dating of the
Quesnelliana to just before the end of the fifth century, probably during the pontificate of Pope Gelasius I (492–496). Older scholarship, beginning with the Ballerinis, argued that the
Quesnelliana was a Gallic collection, though one with an admittedly "Roman colour".
French historians then developed the theory that the collection originated at Arles, which was thought to have been something of a clearing house for canonical materials in the early sixth century. However, more recent scholarship, making much more of the
Quesnelliana’s "Roman colour", has argued for an Italian, possibly even Roman origin. Relatively recent work (in 1985) by Joseph Van der Speeten has shown that the
Quesnelliana, or at least one of its constituent parts (namely the
dossier de Nicée et de Sardique), may have been used as a source for Dionysius's collections. If true, this places the
Quesnelliana definitively at Rome during the first decade of the sixth century. ==Importance and dissemination==