• Northern Francia
• Corbie (?)
• Cambrai (?)
• Péronne (?)

Notre-Dame of Laon

• Computus
• Cosmology
• Liturgy
• Astronomy

• Isidore, De natura rerum (1r-22v)
• Cosmological/computistical compilation titled In nomine Dei summi incipit de astronomia (22v-70v)
• Various blessings and liturgical formulas (71r-72r)
• Added Carthaginian canons (72r-v, continuing on fol. 73r, which belongs to the 2nd C.U.: the two units were probably bound together at an early stage, possibly already during the ninth century).

• Certainly not written in Brittany
• Some contents possibly derive from a Breton exemplar / archetype

Although the specific scriptorium where this ninth-century MS was written remains unidentified, different kinds of evidence appear to converge on Northern Francia—possibly the area of Corbie, Cambrai or Péronne (cf. Bisagni, forthcoming; for an earlier ascription to the Loire Valley, cf. Obrist 1996: 102). As for the date, Bischoff (Kat. §2114) opted for a fairly broad chronological range between the first and the second quarter of the ninth century, but the dating c. AD 820–830, proposed by several scholars (cf. Dell'Era 1979: 271, 282; Obrist 2002: 345; Borst 2006: I, 238; Blume, Haffner and Metzger 2012–16: I, 274), seems plausible.

The compilation De astronomia contains many textual materials of clear Irish origin, especially as far as the chapters on the divisions of time are concerned (these sections even contain three embedded words in Old Irish). These Irish materials were probably excerpted from an Irish computistical tract that can be described as an augmented version of the Hiberno-Latin De divisionibus temporum, or DDT (in this context it should also be noted that a further witness of the same augmented recension, quite heavily re-elaborated and possibly epitomised towards the end of the eighth century, can be found at fols 15r–26v of the important computistical codex Cologne, Dombibliothek, 83-II, written at Cologne between AD 798 and 805). The Irish DDT auctus of Laon 422 shares many unique textual parallels with the Computus Hibernicus Parisinus of AD 754, long sections of which have survived only in two MSS with prominent Breton affiliations: Paris, BnF, Lat. 6400B, copied from a Breton exemplar, and Angers, BM, MS 476, written in Brittany (for the Computus Hibernicus of 754, see Bisagni 2013–14; Bisagni 2019: 247–56; Warntjes 2013–14). This fact raises the theoretical possibility that at least some of the contents of the compilation De astronomia ultimately derived from Irish computistica transmitted through Brittany during the second half of the eighth century. However, it is also possible (and perhaps more likely) that the Irish texts in question reached Northern Francia first, being transmitted to the Loire Valley and Brittany only at a later stage (perhaps as late as the second half of the ninth century). The whole question is still sub iudice, but it should be noted that an edition and a study of the Irish chapters of De astronomia are currently being prepared by Ms Paula Harrison (NUI Galway) in the context of the IrCaBriTT project.

Dobcheva, Aratea-Digital; Bisagni 2019: 264–70; Bisagni 2020a: 30–4; Bisagni, forthcoming; Blume, Haffner and Metzger 2012–16: I, 274–9; BnF Archives et Manuscrits; Borst 2006: I, 238–9; CCfr; Contreni 1978: 31 (n. 4), 47–8; Dell'Era 1979; Fontaine 1960: 37; Innovating Knowledge; LCRC 57–8; 116–17; MPF §95; Obrist 1996: 102, 127; Obrist 1997: 66; Obrist 2002: passim, esp. 343–5; Santoni 2017.

• https://gallica.bnf.fr/ark:/12148/btv1b8492138z