A Stylometric Analysis of Seneca’s Disputed Plays: Authorship Verification of Octavia and Hercules Oetaeus

Description

Purpose

This repository contains the code and data required to replicate the results published in the paper A Stylometric Analysis of Seneca's Disputed Plays: Authorship Verification of Octavia and Hercules Oetaeus. You can access the preprint here.

In this study, we apply stylometry—a computational approach to analyzing writing style—to examine the authorship of two disputed plays attributed to Lucius Annaeus Seneca Minor: Octavia and Hercules Oetaeus. By employing methods such as Principal Component Analysis (PCA), Bootstrap Consensus Tree (BCT), and the Imposters method (o2 verification system), we investigate whether these plays align stylistically with Seneca's undisputed works.

Our aim is to make the study fully reproducible, so this README will guide you step-by-step through the process, from data collection and preprocessing to analysis and validation.

Citation

Paschalis Agapitos and Andreas van Cranenburgh (2024). “A Stylometric Analysis of Seneca’s Disputed Plays. Authorship Verification of Octavia and Hercules Oetaeus”. In: CCLS2024 Conference Preprints 3 (1). 10.2 6083/tuprints-00027394

Structure

This repository is organized into the following directories:

📦 project-root/                     # seneca_stylometry
├── 📁 1_collecting_preprocessing
│   ├──📁 code/preprocessing         # code to preprocess and prepare the data
│   ├──📁 data                       # preprocessed data
│   ├──📁 dataset_perseus_xml        # raw data
├── 📁 2_validation/              
│   ├──📁 validation_PCA_BCT         # code & results for and of the validation of PCA & BCT
│   ├──📁 validation_corpora         # data to perform the validation
│   └──📁 validation_imposters       # code & results for and of the validation of GI
├── 📁 3_analysis/                   
│   ├──📁 code                       # code to perform the analysis using PCA, BCT and GI
│   └──📁 corpora                    # data needed to perform the analysis
│   └──📁 results                    # results of the analysis
├── 📁 docs/                         # Documentation and additional resources
│   └──📄 paper.pdf                  # Preprint of the paper and requirements
│   └──📄 requirements,txt           # libraries and software that need to be installed to prepare the running environment
├── 📄 .gitignore                    # Git ignore file for unnecessary files
├── 📄 LICENSE                       # Project license
├── 📄 LICENSE.md                    # Markdown version of the license
├── 📄 README.md                     # Main documentation file for the project
├── 📄 seneca_stylometry.Rproj       # R project file for Seneca Stylometry

Each directory contains either code or data relevant to a specific step of the analysis process, from preprocessing to validation and final analysis. Follow the sections below to understand how to use each script and dataset.

Code & Datasets

This section provides an overview of the scripts, datasets, and results for replicating our study. The process is divided into two key phases: Validation and Main Analysis.

Validation Phase:

In this phase, we evaluate the effectiveness of the stylometric methods we employ—Principal Component Analysis (PCA), Bootstrap Consensus Tree (BCT), and the Imposters method (GI). We use various corpora of ancient authors to assess the accuracy of these techniques before applying them to Seneca's disputed works.

Here are the scripts, datasets, and results related to the validation phase:

Script	Directory name	Description	Number of distinct authors	Number of texts	Name of distinct authors	Name of distinct work	Results
valid_PCA.Rmd. A detailed list of the parameters used for this experiment can be found in stylo_config.txt	validation_corpus_PCA	The dataset used to validate the PCA method (does not contain Seneca's plays). It is a subset of the works of Lucan, Ovid, Persius, and Statius. The filenames for Amores by Ovid, the fourth Satire by Persius, and the first book of Thebaid by Statius are being renamed using the following format: unknown_{work}.txt.	4	44	Lucan, Ovid, Persius, Statius	Pharsalia, Ars Amatoria, Heroides, Fasti, Ibis. Medicamina Faciei Femineae, Metamorphoses, Epistulae ex Ponto, Remedia Amoris, Tristia	PCA-corr. In paper: Figures: 4a & 4b
valid_BCT.Rmd. A detailed list of the parameters used for this experiment can be found in stylo_config.txt	validation_corpus_BCT	The dataset used to validate the BCT method (does not contain Seneca's plays). It is a subset of the works of Lucan, Ovid, Persius, and Statius. The filenames for Medicamina Faciei Femineae by Ovid, the fourth Satire by Persius, and the first book of Thebaid by Statius are being renamed using the following format: unknown_{work}.txt.	4	44	Lucan, Ovid, Persius, Statius	Pharsalia, Ars Amatoria, Heroides, Fasti, Ibis. Medicamina Faciei Femineae, Metamorphoses, Epistulae ex Ponto, Remedia Amoris, Tristia, Satires, Thebaid, Achilleid, Silvae	BCT/MFCs-4grams. In paper: Figures: 5
valid_imposters_4grams_char.R.	validation_imp_corpus	The corpus used to validate the GI method. It contains all the texts of impostors plus Seneca (excluding the two disputed plays under investigation). Each text becomes the test set and is compared against the others.	9	88	Lucan, Manilius, Martial, Ovid, Persius, Phaedrus, Seneca the Younger, Silius Italicus, Statius, Valerius Flaccus	Pharsalia, Astronomica, Epigrammata, Ars Amatoria, Heroides, Fasti, Ibis. Medicamina Faciei Femineae, Metamorphoses, Epistulae ex Ponto, Remedia Amoris, Tristia, Satires, Fabulae, Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Punica, Achilleid, Silvae, Thebaid, Argonautica	validation_imposters/results. In paper: Figures 6

Main Analysis Phase:

Once the methods are validated, we apply them to the corpus of Senecan plays, with a particular focus on the disputed plays Octavia and Hercules Oetaeus. Here are the details for each analysis scenario:

Script	Directory name	Description	Number of distinct authors	Number of texts	Name of distinct authors	Name of distinct work	Results
pca_sen.R. A detailed list of the parameters used for this experiment can be found in stylo_config.txt	corpus_seneca	the corpus of Senecan plays used for the first experiment in the main analysis phase, where we compare the Senecan plays with each other.	1	10	Seneca the Younger	Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Hercules Oetaeus, Octavia	pca_sen. In paper: Figures 7a & 7b
pca_hero_chunks.R. A detailed list of the parameters used for this experiment can be found in stylo_config.txt	corpus_sen_hero_chunks	the corpus of the Senecan plays but Herc.Oetaeus is split into two halves.	1	11	Seneca the Younger	Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Hercules Oetaeus chunk 1 & 2, Octavia	pca_sen_hero_chunks. In paper: Figures 8a & 8b
pca_sen_stat_ovid.R. A detailed list of the parameters used for this experiment can be found in stylo_config.txt	corpus_pca_bct	The corpus used for the experiments of PCA and BCT with a sample of impostors used.	3	33	Lucan, Seneca the Younger, Statius	Pharsalia, Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Hercules Oetaeus, Octavia	pca_sen_luc_stat.
bct_sen_stat_ovid.R. A detailed list of the parameters used for this experiment can be found in stylo_config.txt	corpus_pca_bct	The corpus used for the experiments of PCA and BCT with a sample of impostors used.	3	33	Lucan, Seneca the Younger, Statius	Pharsalia, Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Hercules Oetaeus, Octavia	bct_sen_luc_stat. In paper: Figures 9
scenario_1_gi.R	gi_scen_1_corpus	The entire corpus of impostors (including the Senecan plays) with the texts untouched. For each disputed play we exclude each other from the test set.	10	104	Lucan, Manilius, Martial, Ovid, Persius, Phaedrus, Seneca the Younger, Silius Italicus, Statius, Valerius Flaccus	Pharsalia, Astronomica, Epigrammata, Ars Amatoria, Epistulae or Heroides, Fasti, Ibis. Medicamina Faciei Femineae, Metamorphoses, Epistulae ex Ponto, Remedia Amoris, Tristia, Satires, Fabulae, Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Hercules Oetaeus, Octavia, Punica, Achilleid, Silvae, Thebaid, Argonautica	Octavia = 1 & Herc. O = 1
scenario_2_gi.R	gi_scen_2_corpus	The entire corpus of impostors (including the Senecan plays) but only Herc. Oetaeus is split exactly in the middle.	10	105	Lucan, Manilius, Martial, Ovid, Persius, Phaedrus, Seneca the Younger, Silius Italicus, Statius, Valerius Flaccus	Pharsalia, Astronomica, Epigrammata, Ars Amatoria, Epistulae or Heroides, Fasti, Ibis. Medicamina Faciei Femineae, Metamorphoses, Epistulae ex Ponto, Remedia Amoris, Tristia, Satires, Fabulae, Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Hercules Oetaeus chunks 1 & 2, Octavia, Punica, Achilleid, Silvae, Thebaid, Argonautica	Octavia = 1 & Herc. O = 1
scenario_3_gi.R. For the preparation of the corpus see cosine_simil.ipynb	gi_scen_3_corpus	The entire corpus of imposters (including the Senecan plays) but from the disputed plays we have removed lines that returned similarity score above 0.6.	10	104	Lucan, Manilius, Martial, Ovid, Persius, Phaedrus, Seneca the Younger, Silius Italicus, Statius, Valerius Flaccus	Pharsalia, Astronomica, Epigrammata, Ars Amatoria, Epistulae or Heroides, Fasti, Ibis. Medicamina Faciei Femineae, Metamorphoses, Epistulae ex Ponto, Remedia Amoris, Tristia, Satires, Fabulae, Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Hercules Oetaeus, Octavia, Punica, Achilleid, Silvae, Thebaid, Argonautica	Octavia = 1 & Herc. O = 1
scenario_4_gi.R. For the preparation of the corpus see 4_split_corpus_chunks.ipynb.	gi_scen_4_corpus	The entire corpus of imposters (including the Senecan plays) split into chunks of 500 tokens.	10	1344 chunks	Lucan, Manilius, Martial, Ovid, Persius, Phaedrus, Seneca the Younger, Silius Italicus, Statius, Valerius Flaccus	Pharsalia, Astronomica, Epigrammata, Ars Amatoria, Epistulae or Heroides, Fasti, Ibis. Medicamina Faciei Femineae, Metamorphoses, Epistulae ex Ponto, Remedia Amoris, Tristia, Satires, Fabulae, Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Hercules Oetaeus chunks 1 & 2, Octavia, Punica, Achilleid, Silvae, Thebaid, Argonautica	GI_results/scenario_4/ In paper: Figures: 10 & 12
scenario_5_gi.R	gi_scen_5_corpus	Corpus of Kestemont et al. (2016), Authenticating Caesar's writings augmented with our gi_scen_4_corpus.	36	3090 chunks	Ammianus Marcellinus, Quintus Asconius Pedianus, Aulus Gellius, Calpurnius Flaccus, M. Tullius Cicero, Quintus Curtius Rufus, Eutropius, Rufius Festus, Florus, G. Julius Hyginus, Titus Livius, Lucius Ampelius, Macrobius, M. Minucius Felix, Nazarius, G. Plinius Caecilius Secundus, Pomponius Mela, Quintus Tullius Cicero, M. Fabius Quintillianus, G. Sallustius Crispus, Seneca the Younger, Seneca the Elder, Suetonius, Tacitus, Valerius Maximus, Varro, Velleius Paterculus, Lucan, Manilius, Martial, Ovid, Persius, Phaedrus, Silius Italicus, Statius, Valerius Flaccus	Res Gestae A Fine Corneli Taciti, Orationum Ciceronis Quinque Enarratio, Noctes Atticae, Declamationes, Academica, Laelius de Amicitia, Pro Archia, Brutus, Pro Caecina, Pro Caelio, Cato Maior de Senectute, De Divinatione, De Fato, De Finibus, Pro Milone, De Natura Deorum, De Officiis, De Optimo Genere Oratorum, Orator, De Oratore, Paradoxa Stoicorum,In Pisonem, De Re Publica, Topica, Tusculanae Disputationes, Historiarum Alexandri Magni Libri Qui Supersunt, Breviarium Historiae Romanae, Festi Breviarium Rerum Gestarum Populi Romani, Epitome De T. Livio Bellorum Omnium Annorum DCC Libri Duo, Fabulae, Ab Urbe Condita Libri, Liber Memorialis, Commentarii in Somnium Scipionis, Octavius, Panegyricus Constantini, Epistularum Libri Decem, Panegyricus, De Chorographia, Commentariolum Petitionis, Declamationes Maiores, Institutiones, Bellum Catilinae, Epistola ad Caesarem I & II, Bellum Iugurthinum, De Beneficiis, De Brevitate Vitae, De Clementia, De Consolatione, Epistulae Morales Ad Lucilium, De Vita Beata, De Ira, Quaestiones Naturales, De Otio, De Providentia, De Tranquilitate Animi, Controversiae, De Vitis Caesarum-Augustus, De Vitis Caesarum-Gaius, De Vitis Caesarum-Divus Claudius, De Vitis Caesarum-Domotianus, De Vitis Caesarum-Galba, De Vitis Caesarum-Divus Iulius, De Vitis Caesarum-Nero, De Vitis Caesarum-Otho, De Vitis Caesarum-Tiberius, De Vitis Caesarum-Tiberius, De Vitis-Caesaris-Titus, De Vitis Caesarum-Divus Vespasianus, De Vitis Caesarum-Vitellius, Agricola, Annales, Historiae, Dialogus De Oratoribus, Factorum Et Dictorum Memorabilium Libri Novem, De Lingua Latina, Rerum Rusticarum De Agri Cultura, Historiae Romanae, Pharsalia, Astronomica, Epigrammata, Ars Amatoria, Epistulae or Heroides, Fasti, Ibis. Medicamina Faciei Femineae, Metamorphoses, Epistulae ex Ponto, Remedia Amoris, Tristia, Satires, Fabulae, Agamemnon, Hercules Furens, Medea, Oedipus, Phaedra, Phoenissae, Thyestes, Troades, Hercules Oetaeus chunks 1 & 2, Octavia, Punica, Achilleid, Silvae, Thebaid, Argonautica	GI_results/scenario_5. In paper: Figures 11 & 13