data ontology

  • document: a discrete unit of text
  • fragment: a discrete piece of material support

A fragment can have more than one document written on it; a document can be comprised of more than one fragment.

manuscript structure

  • folio: a page, including both front (recto) and back (verso)
  • bifolio: a page folded once to yield four writing surfaces (two rectos, two versos)
  • recto: the front of the page
  • verso: the back of the page

In theory, recto should be the side of first inscription. In practice, conservators make the call before the cataloguers and scholars get to it; sometimes the side of first inscription is the one catalogued as verso.

  • quire: several bifolios nested like a pamphlet
  • codex: several quires sewn together to form a book
  • rotulus: a vertical scroll (text is written parallel to the short side of the page)
  • volumen: a horizontal scroll (text is written parallel to the long side in columns)
  • writing support: the material substrate to which the scribe applies ink. In the geniza, rag paper is the most common support, followed by parchment; a few pieces are written on cloth or papyrus

physical condition

  • join: two or more fragments—once part of the same page, quire, or codex—now separated, and sometimes even housed in different collections—which a scholar has matched. The fragments remain physically separate and retain their old shelfmarks, but the scholar who has matched them publishes the join with a “+” between the shelfmarks
  • lacuna: a gap in the text where the writing support has torn


  • discussion: a passage in a book or article in which a scholar has offered an interpretation of a document or part of a document
  • transcription: copy of a document, whether typed or handwritten
  • edition: a transcription that renders the document from manuscript to print
  • paleography: decipherment; also the study of old scripts, often for the purpose of determining when an undated manuscript was written or identifying the scribe who wrote it
  • unpublished edition: an edition from a scholar's corpus not previously published before their inclusion and display in our database; these editions were not found formally printed before digital publication by PGP and are not peer-reviewed as other modern editions might be when published in a book or journal

genres of text

  • legal deed: a contract, testimony or other document produced by or for a legal court, often with probative or dispositive value
  • piyyut: liturgical poetry (Hebrew; pl. piyyutim)
  • responsum: answer to a legal query by a rabbinic authority, usually made in writing (Latin; pl. responsa)

dating and calendar systems

Geniza documents use a range of calendar systems depending on the document’s use and provenance. Many documents are not explicitly dated. For those that are, the dates are included in each entry, both as given on the document and as converted to common era dating. You can also convert dates yourself using this calendar converter.

The following is a non-exhaustive list of the most common dating systems you will encounter in geniza documents, as well as their relationship to common era dates.

  • Common Era (CE): This is the western calendar that we use everyday, originally the Julian calendar, established in 45 BCE (before the common era), then, after the papal calendar reform of 1582 CE, the Gregorian calendar. Converted dates in PGP entries are Julian before 1582, Gregorian after 1582 (regardless of whether the community in question adopted the Gregorian calendar in 1582 or later; in the latter case, this is known as the proleptic Gregorian calendar, and is a convention among modern historians).
  • Anno Mundi (AM): The Jewish calendar, based on the biblical accounts of the world’s creation, calculated from sunset on 6 October 3761 BCE (according to the proleptic Julian calendar). The Jewish calendar as it developed over the first millennium CE is lunisolar: the months are lunar and change with the new moon, but the years must remain in line with the agricultural (solar) calendar. The Jewish months don’t slip backwards as the Islamic months do (see Hijri calendar below). The Jewish year consists of either twelve or thirteen months, alternating in a regular pattern over a nineteen-year cycle, and beginning on 1 Tishri, which falls in late August or September. The months are Tishri (or Tishrei), Ḥeshvan (or Marḥeshvan), Kislev, Ṭevet, Shevaṭ, Adar, Nisan, Iyyar, Sivan, Tammuz, Av and Elul. In leap-years, there is a second month of Adar before Nisan.
  • Hijri calendar (AH): The Islamic calendar, a lunar calendar of twelve months. The lunar year is 11 days shorter than the solar year, so the months slip backwards relative to the solar calendar (so Ramaḍān can fall in any season). The hijrī is calculated from 622 CE, the year when Muḥammad and his followers migrated from Mecca to Medina.
  • Seleucid calendar (Sel. or SE; also Anno Graecorum or AG): Though this calendar is now obsolete in Jewish practice, for the numbering of years, it is the most common calendar found in geniza documents. It is used only for years, and calculated from Seleucus I Nicator’s reconquest of Mesopotamia in 312–11 BCE. There were variants of the Seleucid era used in the Middle Ages. The Seleucid era in Jewish documents was deemed to begin on 1 Tishri 312 BCE. In practice, to convert a Seleucid date to CE, if the day falls before 1 Tishri, subtract 311 from the Seleucid year; if after, subtract 312.
    • Examples:
      • 29 Elul 1311 Sel. = 29 Elul 1000 CE = 1 September 1000 CE
      • 1 Tishri 1312 Sel. = 1 Tishri 1000 CE = 2 September 1000 CE