A palimpsest (//) is a manuscript page from a scroll or book from which the text has been scraped or washed off and which can be used again. The word "palimpsest" comes through Latin palimpsēstus from Ancient Greek παλίμψηστος (palímpsestos, “scratched or scraped again”) originally compounded from πάλιν (palin, “again”) and ψάω (psao, “I scrape”) literally meaning “scraped clean and used again”. Romans wrote on wax-coated tablets that could be smoothed and reused, and a passing use of the term "palimpsest" by Cicero seems to refer to this practice.
The term has come to be used in similar context in a variety of disciplines, notably architectural archaeology.
Because parchment, prepared from animal hides, is far more durable than paper or papyrus, most palimpsests known to modern scholars are parchment, which rose in popularity in western Europe after the 6th century. Also, where papyrus was in common use, reuse of writing media was less common because papyrus was cheaper and more expendable than costly parchment. But some papyrus palimpsests do survive, and Romans referred to this custom of washing papyrus, although the reed from which it was made did not grow in Italy.
The writing was washed from parchment or vellum using milk and oat bran. With the passing of time, the faint remains of the former writing would reappear enough so that scholars can discern the text (called the scriptio inferior, the "underwriting") and decipher it. In the later Middle Ages the surface of the vellum was usually scraped away with powdered pumice, irretrievably losing the writing, hence the most valuable palimpsests are those that were overwritten in the early Middle Ages.
Medieval codices are constructed in "gathers" which are folded (compare "folio", "leaf, page" ablative case of Latin folium), then stacked together like a newspaper and sewn together at the fold. Prepared parchment sheets retained their original central fold, so each was ordinarily cut in half, making a quarto volume of the original folio, with the overwritten text running perpendicular to the effaced text.
Modern decipherment 
Faint legible remains were read by eye before 20th-century techniques helped make lost texts readable. Scholars of the 19th century used chemical means to read palimpsests that were sometimes very destructive, using tincture of gall or later, ammonium bisulfate. Modern methods of reading palimpsests using ultraviolet light and photography are less damaging. Innovative digitized images aid scholars in deciphering unreadable palimpsests. Superexposed photographs exposed in various light spectra, a technique called "multispectral filming," can increase the contrast of faded ink on parchment that is too indistinct to be read by eye in normal light. Multispectral imaging, undertaken by researchers at the Rochester Institute of Technology and Johns Hopkins University, recovered much of the undertext (estimated to be more than 80%) from the Archimedes Palimpsest. At the Walters Art Museum where the palimpsest is now conserved, the project has focused on experimental techniques to retrieve the remaining text, some of which was obscured by overpainted icons. One of the most successful techniques for reading through the paint proved to be X-ray fluorescence imaging, through which the iron in the ink is revealed. A team of imaging scientists and scholars from the USA and Europe is currently using spectral imaging techniques developed for imaging the Archimedes Palimpsest to study more than one hundred palimpsests in the library of St. Catherine's Monastery in the Sinai peninsula.
As a form of destruction 
A number of ancient works have survived only as palimpsests. Vellum manuscripts were over-written on purpose mostly due to the dearth or cost of the material. In the case of Greek manuscripts, the consumption of old codices for the sake of the material was so great that a synodal decree of the year 691 forbade the destruction of manuscripts of the Scriptures or the church fathers, except for imperfect or injured volumes. Such a decree put added pressure on retrieving the vellum on which secular manuscripts were written. The decline of the vellum trade with the introduction of paper exacerbated the scarcity, increasing pressure to reuse material.
Cultural considerations also motivated the creation of palimpsests. The demand for new texts might outstrip the availability of parchment in some centers, yet the existence of cleaned parchment that was never overwritten suggests that there was also a spiritual motivation, to sanctify pagan text by overlaying it with the word of God, somewhat as pagan sites were overlaid with Christian churches to hallow pagan ground. Or the pagan texts may have merely appeared irrelevant. Texts most susceptible to being overwritten included obsolete legal and liturgical ones, sometimes of intense interest to the historian. Early Latin translations of Scripture were rendered obsolete by Jerome's Vulgate. Texts might be in foreign languages or written in unfamiliar scripts that had become illegible over time. The codices themselves might be already damaged or incomplete. Heretical texts were dangerous to harbor: there were compelling political and religious reasons to destroy texts viewed as heresy, and to reuse the media was less wasteful than simply to burn the books.
Vast destruction of the broad quartos of the early centuries of our era took place in the period which followed the fall of the Roman Empire, but palimpsests were also created as new texts were required during the Carolingian renaissance. The most valuable Latin palimpsests are found in the codices which were remade from the early large folios in the 7th to the 9th centuries. It has been noticed that no entire work is generally found in any instance in the original text of a palimpsest, but that portions of many works have been taken to make up a single volume. An exception is the Archimedes palimpsest (see below). On the whole, Early Medieval scribes were indiscriminate in supplying themselves with material from any old volumes that happened to be at hand.
Famous examples 
- The best-known palimpsest in the legal world was discovered in 1816 by Niebuhr and Savigny in the library of Verona cathedral. Underneath letters by St. Jerome and Gennadius was the almost complete text of the Institutes of Gaius, probably the first student's textbook on Roman law.
- The Codex Ephraemi Rescriptus, Bibliothèque Nationale de France, Paris: portions of the Old and New Testaments in Greek, attributed to the 5th century, are covered with works of Ephraem the Syrian in a hand of the 12th century
- The Sana'a palimpsest is one of the oldest Qur'anic manuscripts in existence. Carbon dating indicates that the undertext (the scriptio inferior) was written probably within 15 years of the death of Prophet Muhammad. The undertext differs from the standard Qur'anic text, and is therefore the most important documentary evidence for the existence of variant Qur'anic readings.
- Among the Syriac manuscripts obtained from the Nitrian desert in Egypt, British Museum, London: important Greek texts, Add. Ms. 17212 with Syriac translation of St. Chrysostom's Homilies, of the 9th/10th century, covers a Latin grammatical treatise from the 6th century.
- Codex Nitriensis, a volume containing a work of Severus of Antioch of the beginning of the 9th century is written on palimpsest leaves taken from 6th century manuscripts of the Iliad and the Gospel of St Luke, both of the 6th century, and the Euclid's Elements of the 7th or 8th century, British Museum
- A double palimpsest, in which a text of St John Chrysostom, in Syriac, of the 9th or 10th century, covers a Latin grammatical treatise in a cursive hand of the 6th century, which in its turn covers the Latin annals of the historian Granius Licinianus, of the 5th century, British Museum.
- The only known hyper-palimpsest: the Novgorod Codex, where potentially hundreds of texts have left their traces on the wooden back wall of a wax tablet
- The Ambrosian Plautus, in rustic capitals, of the 4th or 5th century, re-written with portions of the Bible in the 9th century, Ambrosian Library
- Cicero, De republica in uncials, of the 4th century, the sole surviving copy, covered by St Augustine on the Psalms, of the 7th century, Vatican Library
- Seneca, On the Maintenance of Friendship, the sole surviving fragment, overwritten by a late-6th century Old Testament
- Codex Theodosianus of Turin, of the 5th or 6th century
- the Fasti Consulares of Verona, of 486
- the Arian fragment of the Vatican, of the 5th century
- the letters of Cornelius Fronto, overwritten by the Acts of the Council of Chalcedon
- the Archimedes Palimpsest, a work of the great Syracusan mathematician copied onto parchment in the 10th century and overwritten by a liturgical text in the 12th century
- Sinaitic Palimpsest, the oldest Syriac copy of the gospels, from the 4th century
- the unique copy of a Greek grammatical text composed by Herodian for the emperor Marcus Aurelius in the 2nd century, preserved in the Österreichische Nationalbibliothek, Vienna
- Codex Zacynthius – Greek palimpsest fragments of the gospel of Saint Luke, obtained in the island of Zante, by General Colin Macaulay, deciphered, transcribed and edited by Tregelles
- Codex Dublinensis (Codex Z) of St. Matthew's Gospel, at Trinity College, Dublin, also deciphered by Tregelles
- Codex Guelferbytanus 64 Weissenburgensis, with text of Origins of Isidore, partly palimpsest, with texts of earlier codices Guelferbytanus A, Guelferbytanus B, Codex Carolinus, and several other texts Greek and Latin;
- Other palimpsests (New Testament)
To the present day survived about sixty palimpsest manuscripts of the Greek New Testament. Uncial codices:
Porphyrianus, Vaticanus 2061 (double palimpsest), Uncial 064, 065, 066, 067, 068 (double palimpsest), 072, 078, 079, 086, 088, 093, 094, 096, 097, 098, 0103, 0104, 0116, 0120, 0130, 0132, 0133, 0135, 0208, 0209.
Extended usages 
- The word palimpsest also refers to a plaque (in particular a monumental brass) which has been turned around and engraved on what was originally the back. This usage was coined by Albert Way in a paper published in Archaeologia in 1844.
- In planetary astronomy, ancient craters on icy moons of the outer Solar System whose relief has mostly disappeared, leaving behind only an albedo feature or a trace of a rim, are also known as palimpsests or ghost craters
- In medicine it is used to describe an episode of acute anterograde amnesia without loss of consciousness, brought on by the ingestion of alcohol or other substances: 'alcoholic palimpsest'.
- The term is used in forensic science or forensic engineering to describe objects placed over one another to establish the sequence of events at an accident or crime scene.
- Several historians are beginning to use the term as a description of the way people experience times, that is, as a layering of present experiences over faded pasts.
- Palimpsest is beginning to be used by glaciologists to describe contradicting glacial flow indicators, usually consisting of smaller indicators (i.e., striae) overprinted upon larger features (i.e., stoss and lee topography, drumlins, etc.).
- During the opening credits of the film version of The Name of the Rose, it is described as "A palimpsest of the novel by Umberto Eco".
- Gore Vidal titled his 1995 memoir Palimpsest.
- The contemporary British composer George Benjamin has written a pair of orchestral pieces titled Palimpsest I and Palimpsest II.
- The term is also used to describe augmented realities brought about by the melding of layers of material places and their virtual representations.
- A season 9 episode of Law & Order: Criminal Intent is titled "Palimpsest."
- Sherlock Holmes studies a fifteenth century palimpsest as an antidote to ennui prior to the action starting in The Adventure of the Golden Pince-Nez.
- Palimpsets are featured prominently in the Elizabet Lowell novel Moving Target.
Architects, archaeologists and design historians sometimes use the word to describe the accumulated iterations of a design or a site, whether in literal layers of archaeological remains, or by the figurative accumulation and reinforcement of design ideas over time.
Whenever spaces are rebuilt or remodeled, evidence of former uses remain. Examples include: tarred rooflines remain on the sides of a building after the neighboring structure has been demolished and dust lines after an appliance is relocated. An excellent example of a building with many instances of this is The Tower of London, where construction began in the 11th century and continues into the 21st.
Egyptologists use the word for texts and representations inscribed in stone that have been scraped away, either completely or partially, often with a plaster filling being applied, and then a new inscription carved on top.
- Codex Nitriensis
- According to Suetonius, Augustus, "though he began a tragedy with great zest, becoming dissatisfied with the style, he obliterated the whole; and his friends saying to him, What is your Ajax doing? He answered, My Ajax met with a sponge." (Augustus, 85). Cf. a letter of the future emperor Marcus Aurelius to his friend and teacher Fronto (ad M. Caesarem, 4.5), in which the former, dissatisfied with a piece of his own writing, facetiously exclaims that he will "consecrate it to water (lymphis) or fire (Volcano)," i.e. that he will rub out or burn what he has written.
- "In the Sinai, a global team is revolutionizing the preservation of ancient manuscripts". Retrieved 2012-09-07. Text "Washington POST Magazine Sept. 8, 2012" ignored (help)
- The most accessible overviews of the transmission of texts through the cultural bottleneck are Leighton D. Reynolds (editor), in Texts and Transmission: A Survey of the Latin Classics, where the texts that survived, fortuitously, only in palimpsest may be enumerated, and in his general introduction to textual transmission, Scribes and Scholars: A Guide to the Transmission of Greek and Latin Literature (with N.G. Wilson).
- The Institutes of Gaius, ed W.M. Gordon and O.F. Robinson, 1988
- Sadeghi, Behnam; Goudarzi, Mohsen (March 2012). "Ṣan'ā' 1 and the Origins of the Qur'ān". Der Islam. Retrieved 2012-03-26.
- Graham, M. 2010. Neogeography and the Palimpsests of Place. Tijdschrift voor Economische en Sociale Geografie. 101(4), 422-436.
|Wikisource has the text of the 1911 Encyclopædia Britannica article Palimpsest.|
- OPIB Virtual Renaissance Network activities in digitizing European palimpsests
- Brief note on economic and cultural considerations in production of palimpsests
- PBS NOVA: "The Archimedes Palimpsest" Click on "What is a Palimpsest?"
- Rinascimento virtuale a project for the census, description, study and digital reproduction of Greek palimpsests
- Ángel Escobar, El palimpsesto grecolatino como fenómeno librario y textual, Zaragoza 2006