The bulk of the Thesaurus Linguae Latinae, as it appears on the shelf, consists of articles about Latin words themselves: an entry for nam, another for ponere, and so forth. In addition to these volumes that chronicle Latin’s many words, the Thesaurus also publishes an Index, a reference work for the various abbreviations used in Thesaurus articles and (more importantly) for the editions and sources of texts cited in the dictionary. As the preface to the Index explains:
The Index should enable every user of the Thesaurus to identify and locate all passages cited. Its abbreviations have been adopted by a large number of publications in the field of ancient philology. As an added benefit, the Index offers a concise overview of nearly all available Latin texts of antiquity, from both literary and non-literary sources. It may be useful, therefore, to consult the Index even independently of the Thesaurus itself.
The first edition of the Index was published in 1904. The present on-line version is based on the revised printed edition of 1990, edited by C. G. van Leijenhorst and D. Krömer. Here newly available texts have been and will continue to be incorporated, as will changes in any of the abbreviations used in citing works (you can also download the Addenda Indici here). New editions which do not require any changes in these abbreviations will normally not be mentioned in the Index. It is assumed that the reader is aware of them.
This summer, the editors of the Thesaurus have produced an on-line version of the Index, which has the double benefit of allowing easier updates and of facilitating access to this great resource. As the text above states, the Index is indispensable for deciphering the Thesaurus, but it can also be helpful to consult if you’re just looking for, say, a reliable edition of Apuleius or a quick summary of the works of St. Ambrose.
As is the case with the Thesaurus, the Index takes some getting used to: it uses its own conventions for alphabetizing, numbering, and so forth. (You can read an in-depth explanation of these conventions at the Thesaurus website.) To help scholars excavate its information, I’ve written up some basic tips here along with an example explanation of how to read the Index’s listings for Vergil, shown in the screenshot below:
The Index presents information five columns. The first three columns provide basic data about authors and their works: the first columns gives dates (if known), the second gives the name of an author or text as written in Thesaurus articles, and the third gives alternative naming conventions (in the case of changes during the compilation of the Thesaurus). For Vergil, the first column shows his birth in the year 70 (signified by the asterisk) and his death in the year 14 (signified by the dagger/obelisk). Using the information from the second column, we might cite a line from the Aeneid as VERG. Aen. 4, 134 or one from the Georgics as VERG. georg. 3, 13. (Note: Your browser may not have rendered the author’s name in small capitals. Also, the numbers provided in the second column of the Index are the final line/paragraph/locus of that particular work — e.g., the last line of the Aeneid is 12, 952.)
For those getting into the nitty-gritty of a particular text or author, the fourth and fifth columns may be of interest. In the fourth, one finds explanations of the sources and other relevant information about the texts, for example that the eclogae of Vergil are also called the bucolica and that the fragmentary text of the epistulae ad imp. Augustum is preserved in Macrobius’ Saturnalia. And in the fifth column, one finds information about the various (and most reliable) editions.
Like the Thesaurus itself, the Index conveys lots of specialized information for several authors, including cross-references to the Beuron Vetus Latina citations and relevant translations to and from ancient Greek works. To learn more about this more technical material and to see a list of abbreviations for frequently cited editions, consult the extended “Directions for Use.” But the simplified instructions above should give you a decent grasp of the Index and help you use it as an authoritative and comprehensive reference for the available Latin texts from antiquity.