During the 17th century, a significant number of collaborations emerged between playwrights, among which authors as famous as Pierre Corneille, Thomas Corneille or Molière, as well as Philippe Quinault or Jean Donneau de visé. The actual division of labour between authors can sometimes be deduced from historical documents, but is most of the time uncertain. In this paper, we try to address this question by using the information we got from one specific instance of collaboration: Psyché (1671). We first try to assess the accuracy of the notice to the reader of the printed edition of the play, where each author's involvement is clearly claimed, using machine learning and “rolling stylometry” methodology. We then use the optimal parameters already applied to this play to analyse other collaborative works of the time, in particular cases of potential collaboration between Thomas Corneille and Jean Donneau de Visé in Circé and L'Inconnu.
Yet, the task raises a number of difficulties. First, style change detection is not a completely solved problem, and even recent competitions [30] have shown that precisely determining style breaches, i.e. places where the authorship switches in a collaborative text, was still a complex task.
The task is all the more complicated for French 17th century plays, known as “théâtre
classique”. The 17th century is a time when the notion of authorship settles in France [
French playwrights do not refrain from imitating or adapting whichever text is likely to be presented on a stage, sometimes without even bothering to make significant additions or to add characteristics from their own literary style [23].1
Strongly codified, building their plots on the same Spanish, Italian, Greek or Latin models,
these plays are often very homogeneous, which makes it more difficult to properly attribute
texts . In particular, similarities induced by the literary genre or subgenre can be as strong as
similarities induced by the authors’ idiolect [
Imitation could even go to the point of piracy or plagiarism, such as attempting to steal
another author play, or led to disputes about the true source of a story. The polygraph and
literary “entrepreneur” Donneau de Visé [28] – famous later on as the as the powerful founder
and editor of the monthly Mercure Galant, a collective literary periodical that published a
mix of recycled manuscript or printed pieces, reader contributions (poems, etc.) and his
own original material – was familiar of such practices at least in his early career. He more
or less started his career by trying to steal Sganarelle ou le cocu imaginaire from Molière:
before Molière could publish himself his own play, Donneau published in 1660, with the help
of the printer Jean Ribou, both a pirate edition of Molière’s Sganarelle, in which he added
his commentaries and that he went to the point of dedicating to Molière himself (!), and a
plagiarised play, La Cocue imaginaire, where he reversed masculine and feminine roles [
A final challenge is related to the diverse potential nature of collaborative writing.
According to Pennebaker and Ireland [
As we well see, suspected collaborative writing cases in 17th century French theatre – even though we might suspect them on declarative grounds to fall mainly in the first “Just-likeanother-member-of-the-team hypothesis” – also presents clue of a division of the work on diferent authorial levels, for instance content versus form, narrative versus versification.
To help us address the various collaborative authorship problems raised by the writings of this century, we thus try to work on one of the best documented collaboration of the time: Psyché.
1All translations are our own.
Psyché is a tragedy-ballet in five acts, written in free verse, and created in 1671, during the
very long festivities following the peace of Aix-la-Chapelle in 1668. It originates in Louis XIV’s
desire to give a new show in the “Salle des Machines” of the Tuileries Palace. Built in 1660
by renowned architect Louis Le Vau, this theatre took its name from the machinery designed
by Gaspare, Carlo and Lodovico Vigarani, allowing for spectacular efects and complex set
changes [
In 1758, Lagrange-Chancel reported in the preface to his own Orphée that several authors would have proposed a project for this occasion.
The late King having resolved to give to all his court one of these great
celebrations in which he liked to have a rest from his works, wanted to take advice from
Racine, Quinault, and Molière, which, among the the great geniuses of this century,
he regarded as the most capable of contributing, by their talent, to the
magnificence of his pleasures. To that efect, he asked them to pick a subject for which
they could use an excellent decor representing the underworld, kept safe and sound
in the furniture storage unit. Racine proposed the subject of Orphée; Quinault,
the abduction of Proserpine, which he subsequently turned into one of his most
beautiful operas; and Molière, with the help of the great Corneille, championed the
subject of Psyché, which prevailed over the two others [
Through the correspondence of the Vigaranis, we know that the decision to give this Psyché at the Salle des Machines was made only a few weeks before it was played. In a letter written on December 12th, 1670, Vigarani explained that they were “preparing a great show, to be performed for the Epiphany at the Tuileries theatre” [24], The imminence of the deadline forced everyone to rush to get the work done. As stated in a letter written on December 15th, 1670, “Carlo is very busy because of the show prepared for the Epiphany. He is very tired. He is doing his best to please the King, but he doubts he will be strong enough to continue.”
The lack of time apparently had consequences on Molière’s ability to finish the play. This led to a singularity: an official account of each author’s implication. In a notice from the publisher “au lecteur” (to the reader), we find this explanation on how the work is supposed to have been divided:
This work is not written by a single hand. Mr Quinault wrote all the poetry of the parts set to music, except the Italian Complaint. Mr de Molière wrote the outline of the play, set its arrangement - he focused more on the beauties and the pump of the show than on its strict observance of the rules. Regarding versification, he did not get the time to execute it in its entirety. Carnival was approaching, and the insisting demands of the King, who wanted to entertain himself several time before Lent, forced him into accepting some assistance. Thus, only verses from the Prologue, the First Act, the first scene of the Second Act, and the first scene from the third Act are his work. Mr. Corneille used two weeks to versify the rest; and this way, His Majesty’s orders were satisfied in time [ 20].
Does this notice to the reader seem plausible? The situation where the King’s urgent demands change the author’s agenda was not unprecedented. For instance, when in 1664, Louis XIV commissioned a new play with ballet to Molière for the “Plaisirs de l’île enchantée” festivity in Versailles, the latter could not finish in time the versification of his play. As stated in its first edition [ 19], “an order from the King, who pressed this matter, forced [the author] to finish all the rest in prose.” Only thirty percent of La Princesse d’Elide is thus in verse, the rest being in prose.
Stylistic studies also seem to confirm the plausibility of this notice. Psyché is one of the
rare examples of mixed verses by their authors. Before that, Pierre Corneille had only used it
once, in Agésilas in 1666. The same goes for Molière, who also mixed various types of verses in
his Amphitryon in 1668. And the way the two authors use mixed verses is diferent [
Without taking this notice “to the reader” for granted, we can consider that it gives
potentially truthful information regarding the play, that we will first try to disprove or verify.
1.3. Hollywood in the 17th century: Special efects, music and the “ Pièces à
machines”
Psyché raises a few specific concerns because of its genre. This play is indeed a rare instance
of pièce à machines, a subgenre very much in favour between the 1650s and the 1670s, but
of which only 15 plays or so have been composed [
But other authors followed him, sometimes collaborating to produce that kind of plays, like
Thomas Corneille (Pierre Corneille’s younger brother) and Jean Donneau de Visé. Amongst
the most impressive shows of the time, the first collaboration between the two authors, Circé
(1675), encouraged them to work together for other works. This play was thus quickly followed
by another collaboration: L’Inconnu (1675). It seems that Donneau de Visé’s implication in
this play could be very significant. It draws its inspiration from Donneau de Visé’s own
tenth short story [
Yet, despite these claims, the only name cited in the “Privilège du roi” of the first printed edition is Thomas Corneille. Why omitting to mention Donneau de Visé? We know from the Registre de La Grange that Donneau de Visé was payed fees for the writing of the play, and he received the same amount for it as Thomas Corneille. It is thus historically extremely unlikely that Donneau de Visé would not have contributed to the play. But did he overstate his implication in the writing of the play? Or were there only “commercial reasons” to avoid mentioning his name - Thomas Corneille being more respected as a playwright than he was?
Thus, using the parameters found optimal in our benchmark phase, and then tested on Psyché, we will try to work on Circé and L’Inconnu, two pièces à machines also written in verse and allegedly written collaboratively.
The scarcity of “pièces à machines” however makes it challenging to build a stylometric approach only on a subgenre-specific approach. We thus compare two methods in this paper: a genre-specific approach, on a small dataset, and a cross-genre approach, on a considerably larger dataset (see appendix A).
To investigate these difficulties, we built two diferent analytic setups, with two very diferent
philosophies:
a genre-specific approach , in which we built a training corpus including one play from the
same subgenre for each of the three involved authors, as well as two control authors –
one play by Boyer, and two plays for Quinault, as his plays were significantly shorter (see
appendix A.1.1). We then benchmarked diferent sample lengths, using a leave-one-out
approach. We lacked sufficient data to include Thomas Corneille in this setup, because
the two available plays that could fit the definition, Circé and L’Inconnu are suspected
to be collaborations with Donneau de Visé that we want to analyse later on.
a cross-genre approach in which we took all available single-author verse or mixed plays
containing more than 400 verses from each candidate in the Théâtre classique corpus
[
For each case studied, the set of candidate authors is known. We thus use an authorship attribution rather than an authorship verification setup.
In terms of features, after suppressing editorial punctuation and lowercasing the texts, we
extract character 3-grams, a standard choice in authorship attribution [
The chosen size of the sample can be seen as a trade-of between accuracy and granularity: the
smaller the samples are, the better the “resolution” of the analysis and the ability to locate
precise stylistic breaks or identify limited shifts in hands [10]; the bigger they are, the more
statistically reliable is our computation, with optima often observed in the 2500-5000 words
range [
Detailed scores for the retained sample length on the cross-genre corpus show that Boyer is the best recognised, while precision for Donneau de Visé and Molière is better (the model is never wrong in attributing plays to them) than recall (the model misses a few samples), while the opposite is true for both Corneille brothers (Table 2).
Once the sample size of 150 verses chosen, we train a final SVM model for each setup, on the complete training set, and then, following rolling stylometry methods, we apply this model to every successive portion of length n, with a step of 1 (and so, an overlap of n − 1 between two successive portions, e.g., verses 1-150, 2-151, 3-152…). We then extract the classification, and plot the decision function for each classifier.
Like with many geometrical methods, this type of analysis rests on the representation of texts or samples as points in a high dimensional space, based on the frequency of the selected features. In our case, the frequency of each type of character 3-grams are used as a coordinate on one axis of an high-dimensional space.
A support vector machine computes a hyperplane in this high-dimensional space, in order to achieve the best separation between two sets of dots (i.e., text from author 1, text from all other authors). Intuitively, a good separation is achieved by the hyperplane that has the largest distance to the nearest training data points of any class (called functional margin), since in general the larger the margin the lower the generalisation error of the classifier.
The decision function tells us how close each sample is to the hyperplane separating each class. A negative value means that the sample is outside, a positive, inside. The higher the score, the deeper inside the class is located a dot, which can be interpreted as a strength of the authorial markers or an increase in the confidence of the classifier.
By monitoring the decision function of all candidate authors, we can see when a portion of the text is getting closer to the style of an individual author. When the value of the decision function for one author gets high, while the values for all others remain low, it is easy to attribute this portion to this candidate. Yet, in the case where all decision function would decrease or remain low simultaneously, the status of the portion is hard to assess, and could be alternatively attributed to a synergy between several candidates, to the intervention of an author outside the set or could be the results of some kind of noise, in particular generic discrepancies between the training set and the portion being assessed.
Each sample’s horizontal placement on the graph is determined by its median point, in verses (fig. 1). For instance, the score attributed to the sample ranging from the 400th to the 550th verse will be placed at the 475th verse. This implies a small but significant distortion regarding the placement of each score in the timeline of each play. It must be taken into account when reading the graph.
3.1. Psyché by P. Corneille, Molière and Quinault Both setups provide globally consistent results. The end of the prologue, most of the first act, and the beginnings of the second and the third acts are attributed to Molière. Molière’s imprint then seems to gradually fade away, while Pierre Corneille’s contribution appears constantly growing throughout the play. This result seems solid, and even conservative regarding Molière’s share of the work. When using the cross-genre setting, the precision for Molière is 100 % while the recall is lower, at 0.75 % (Table 2). On the opposite, the recall for Pierre Corneille is perfect (100 %), while the precision is lower (86 %). This setting should thus underestimate Molière’s participation in the play. Yet, even this computation confirms that the statements made in the notice from the publisher to the reader regarding him are globally accurate. A small but interesting diference between our analysis and the notice concerns the spike of Corneille’s decision function at the end of the first act. According to it, it could be possible that Corneille had a hand in finishing the first act, under a fashion comparable to that of the other acts (begun by Molière, ended by him) but in much smaller proportions, considering the brevity of scenes 4 to 6 of the first act (forty verses in total).
Performance on Quinault is also satisfying, even if his interventions can be sometimes quite short: his alleged part in the prologue barely exceeds 50 verses, his “second intermède” is less than 20 verses long etc. His intervention in the prologue is a bit masked by the 150 verses window. Yet, we can see that the decision function for Quinault is high at the very beginning. The finale (“ Cinquième intermède”) and the 60-verse long “troisième intermède” at the end of the third act are quite visible, and attributed to Quinault, which is consistent with the notice to the reader. Even the very short “second intermède” is detected by both methods, and especially clearly in the genre-specific approach. 2 3.2. ‘Circé’ by T. Corneille and J. Donneau de Visé If we consider the results of the cross-genre setup on ‘Circé’ (fig. 2) – the only setup with training material for Thomas –, the major implication of Thomas Corneille in the writing of this play is self-evident. Donneau de Visé seems to rise during a small passage of the prologue, somewhere around the third scene or perhaps the “Prologue de la musique et de la comédie” (accounting for the blurriness due to window size), a part of sung dialog, which would be consistent with some of his claims. Yet, no other passage emerges that would make it even seem plausible that he partly versified them.
The spike of Quinault at act 2, scene 7 matches also a sung dialog (“dialogue de Sylvie et de Tircis, qui se chante”). Quinault obviously knew how to write passages to be sung and collaborated with Thomas Corneille in other occasions. Did Donneau de Visé have another try at plagiarism, after having experimented with such practices earlier in his career? Or did Donneau or Thomas Corneille ask a small amount of help to a colleague for a specific passage? Without further analysis, it is difficult to answer, yet it is to be noted that the value of the decision function only barely crosses 0 (implying positive class membership) on one single point. This could be an artefact due to generic attractions, because Quinault produced an important number of musical texts, represented in the training material. It is in any case deserving of further investigation before drawing any firm conclusion. 3.3. ‘L’Inconnu’ by T. Corneille and J. Donneau de Visé When applying the same method on L’Inconnu (fig. 3), here again, Donneau de Visé’s implication is hard to assess, while Thomas Corneille’s style seems easily recognised. Small passages for which he claims authorship could well be too difficult to detect which such windows - but appeared in Psyché. Here, the decision function seems barely afected. It is to be noted that 2It is to be noted that we removed the “Premier intermède”, written in Italian (by Lully), for obvious reasons. the value of the decision function for Thomas collapses below 0 on a few occasions, especially during the long dialogues at the end of act 1 and act 2. This could also receive an interpretation based on generic discrepancies between the training set and this part of the text.
On Psyché the results of the rolling analysis verifies very closely the self-declaration of the notice. In comparison, we seem only to identify a non declared limited intervention of Corneille at the end of the first act.
Our results seem to confirm that Donneau de Visé’s contribution to the final writing of the
plays he co-signed with Thomas Corneille was quite scarce. This of course does not mean
that his contribution to those plays was non-existent. Stylometric analyses such as the ones
performed here mostly detect the style of the person who actually wrote the last version of
the sentences. Thomas Corneille for instance versified Molière’s famous comedy in prose, Dom
Juan, after his death and stylometry attributes the play to Thomas Corneille without a blink
[
In broader terms, the clues gathered here seem to point mainly towards the first case of
collaborative writing described by Pennebaker and Ireland [
Further research are still needed to confirm and extend the results on Circé and L’Inconnu, and more generally on collaborative writing during this age. Increasing the size of the training set, especially for Donneau de Visé could be a first lead. In particular, we were not able to secure access to usable digital text of plays such as Les Amours de Vénus et d’Adonis (1670) or Amours de Bacchus et d’Ariane (1672), two pièces à machine he wrote alone during the same decade as his collaborations with Thomas Corneille. Running an efficient OCR and postcorrection of those texts, already digitised by the Bibliothèque nationale de France, should thus be an important next step.
In terms of analysed features, we could extend our work to account for metrical features [22], accounting for instance for verse length in syllables, and the sequence of such lengths in the “vers libres” parts. We could also try to cross stylistic with thematic features, to further investigate contribution to the plot by opposition to contributions to the versification.
The Quinault spike in Circé could also make us think that generic attractions are still an issue in our study: having written numerous opera librettos, Quinault could be a designated candidate for whatever looks like a sung passage to our SVM model. We should thus check for possible imbalances in the training corpus. First experiments however seem to show that our results stay even when downsizing Quinault’s sung passage in the training set.
Finally, we could extend our process to collaborations in prose - which were quite numerous in the théâtre classique in general, and which also occurred in a pièce à machines such as La Devineresse by Thomas Corneille and Jean Donneau de Visé.
Code and datasets are available at 10.5281/zenodo.5517801.
We thank Pr. Georges Forestier for his input on Psyche and the subgenre of “pièces à machines”, Thibault Clérice for fruitful discussions on machine-learning and stylometry, and anonymous reviewers for their careful reading and insightful suggestions. Errors remain our own.
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A.1.1. Train (with leave-one-out test) author title Boyer, Claude LES AMOURS DE JUPITER ET DE SÉMÉLÉ, TRAGÉDIE Corneille, Pierre LA CONQUÊTE DE LA TOISON D’OR, TRAGÉDIE Donneau de Visé, Jean LES AMOURS DU SOLEIL, PASTORALE. Molière Amphitryon, Comédie Quinault, Philippe THÉSÉE, TRAGÉDIE Quinault, Philippe CADMUS et HERMIONE, TRAGÉDIE
A.2.1. Train author Boyer, Claude Boyer, Claude Boyer, Claude Boyer, Claude Boyer, Claude Boyer, Claude Boyer, Claude Boyer, Claude Boyer, Claude Boyer, Claude Boyer, Claude Boyer, Claude Corneille, Pierre author Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Pierre Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Corneille, Thomas Donneau de visé, Jean Donneau de visé, Jean Donneau de visé, Jean Donneau de visé, Jean Donneau de visé, Jean Donneau de visé, Jean Donneau de visé, Jean Molière Molière Molière Molière Molière Molière Molière Molière Molière Molière Molière Molière Quinault, Philippe Quinault, Philippe Quinault, Philippe Quinault, Philippe n. words 16439 18913 18273 18226 18001 18313 16383 19191 18411 19614 18327 17623 15921 15897 20284 18730 19189 18583 19229 20532 19119 19334 15076 18642 19085 20041 18885 20353 17188 18771 19451 18803 22779 19310 19823 20384 18737 19730 13758 20702 19698 17025 20697 20512 19482 18651 20223 21978 20794 19230 20419 9659 19903 18121 19953 21509 21246 21267 18863 19804 20898 6278 8203 7413 11179 11907 6123 17603 19021 19377 12161 21708 9607 19135 6328 19590 10951 6877 21088 4733 6811 9181 6840 title LA COMÉDIE SANS COMÉDIE, COMÉDIE LES COUPS DE L’AMOUR ET DE LA FORTUNE, TRAGI-COMÉDIE LE DOCTEUR DE VERRE, COMÉDIE LE FANTOME AMOUREUX, TRAGI-COMÉDIE LES FÊTES DE L’AMOUR ET DE BACCHUS, PASTORALE LA GÉNÉREUSE INGRATITUDE, TRAGI-COMÉDIE PASTORALE ISIS, TRAGÉDIE en MUSIQUE LA MÈRE COQUETTE ou LES AMANTS BROUILLÉS, COMÉDIE PERSÉE, TRAGÉDIE PROSERPINE, TRAGÉDIE ROLAND, TRAGÉDIE EN MUSIQUE STRATONICE, TRAGI-COMÉDIE LE TEMPLE DE LA PAIX, BALLET THÉSÉE, TRAGÉDIE n. words 18625 18884 20996 17723 19181 17932