A [syngraphe] (συγγραφή) may take the form of a double document, ie. the text of the contract or receipt is written out twice on the same sheet of papyrus. For an overview of all types of double documents, see [Wolff 1978a : 57-80].
Six-witness double document
The earliest form of double document, appearing in Greek from the late IV BCE, is the six-witness double document (συγγραφὴ ἑξαμάρτυρος), a privately drawn up contract with the upper/inner text (scriptura interior) rolled up and sealed, and the lower/outer text (scriptura exterior) open and available for consultation [5836 311-310 BCE; 5837 285-284 BCE (with seals), both Elephantine]. The six witnesses were named at the end of each of the two scripts, one of which was nominated the συγγραφοφύλαξ (keeper of the syngraphe) and entrusted with the finished document. On probable demotic precedents for this double document consult [Wolff 1978a : 59-63]. These documents record loan contracts [3097 110 BCE; 3099 109 BCE, both Hakoris], marriage agreements [5836; 5838 284-283 BCE, Elephantine], and testaments .
Although it became possible to publicly register private contracts by the end of the III BCE [P.Dion : 177], the II BCE saw an increase in the number of officials (agoranomoi) with the authority to register documents in a grapheion; see [Wolff 1978a : 9-18] on the office of the agoranomos. This registration led to a gradual degeneration of the six-witness double document, with the inner script eventually shrinking to a one-line summary, compare [5837; 2674 215-214 BCE, Oxyrhynchite nome; 44733 145 BCE, Herakleopolis; 8140 130 BCE, Hermonthis; 3099]. While the requirement for six witnesses and a συγγραφοφύλαξ was now superfluous, there were documents which still listed these alongside the note of registration, e.g. [3097; 869382 99 BCE, Herakleopolite nome]; see [Wolff 1978a]. Eventually, by the end of the I BCE, even the single line inner script had disappeared, and all that remained of the six-witness double document was the word μάρτυρες (witnesses), a remnant of a now obsolete requirement [10235 l.27, 3 CE, Philadelphia].
The Roman period six-witness document, a δάνειον ἑξαμάρτυρον, bears little resemblance to the Ptolemaic six-witness double document. On theories surrounding the origin of this type of document see [Wolff 1978a : 72-73, esp. n.85].
Double documents, without six-witnesses or a συγγραφοφύλαξ, were drawn up and registered in the grapheion. They also have an inner and outer script, are rolled and sealed, and mostly concern house and land sales, e.g. [56; 91, both 113 BCE, Pathyris]. These documents are often referred to as agoranomic deeds; see [Pestman 1985] for such documents from Krokodilopolis and Pathyris.
On six-witness double documents, see [Wolff 1978a : 57-71] and [Pestman 1980 : 9-13]. On the evolution from private document to agoranomic deed, see [P.Dion : 176-193] and [Yiftach-Firanko 2008b].
Another type of double document also found in the Ptolemaic period is the symbolon, a contract or receipt written out twice on a single sheet (scriptura interior / exterior), and sealed. The inner script is more usually an abstract of the contents of the outer script. Many of the examples extant belong to the Zenon archive; most of them are receipts for grain [762 257 BCE, Philadelphia], tax [2063 249-248 BCE, Philadelphia (pig tax)], money [1834 257 BCE, Philadelphia], or wages [1837 257 BCE, Philadelphia] - the last two examples have a demotic copy after the two Greek scripts. A contract for a loan of wheat was explicitly drawn up as a symbolon: ἀποδώσω κατὰ τὸ σύμβολον τ[οῦτο... ‘I will give according to this symbolon’ [3132 Frag.B, l.19, 22, 257 BCE, Oxyrhynchite nome]. See [Wolff 1978a : 75-77].
Other symbolon receipts were issued by naukleroi (ship-owners) to various sitologoi (grain collectors) upon receipt of grain from the granaries given to them for shipment, e.g. [3066 197 BCE, Arsinoite nome]. See [Pfeiffer 2003 : 25-26] for a full bibliography on these documents.
The Ptolemaic six-witness double document begins with the [date@start], usually the long regnal format for both inner and outer scripts, e.g. [2946 171 BCE, Arsinoite nome; 44733], or a short date for the inner script and a full regnal date for the outer script, e.g. [3741 103 BCE, Arsinoite nome], or a short date at the beginning of both parts, e.g. [764 257 BCE; 767 256 BCE, both Arsinoite nome].
The main text begins directly with the verb describing the action in an objective statement, e.g. [ἐδάνεισεν name <nom.>][to name <dat.>], ‘N has loaned to N’, [2674; 2650 173 BCE, Arsinoite nome], or [ἐμίσθωσεν name <nom.>][to name <dat.>], ‘N has leased to N’, [2946 171 BCE, Tebtunis]. At the end of the main text there is a validation statement: ἡ συγγραφὴ ἥδε κυρία ἔστω [5836 l.13-14; 869382 l.21-22]. A list of witnesses follows, introduced by [μάρτυρες] e.g. [44733 l.42; 869382 l.22], after which the [συγγραφοφύλαξ] is named [2650 l.18]. A document settling a dispute is drawn up with a [ὁμολογεῖ + infinitive] construction, in this case as a mutual homologia: ὁμολογοῦσιν διαλελύσθαι πρὸς ἀλλήλους ‘we agree together that we have settled’ [8060 260 BCE, Hibeh].
Double documents registered in the grapheion have an inner script which is a summary or abstract of the main text, beginning with a short [date]. After the [date] in the outer script, the [place] and name of the agoranomos follows [78 l.18-19 99 BCE, Pathyris]. The main verb begins the objective statement [ἀπέδοτο name <nom.>] ‘N sold’ followed by a description of the property, and another objective statement introduces the buyer [ἐπρίατο name <nom.>] ‘N bought’, e.g. [84 l.17, l.20, 123 BCE, Pathyris]. A registration docket is placed after the main text [name <nom.> κεχρημάτικα] . This can be followed in some instances by a [bank diagraphe] .
Receipts usually comprise a short [date] followed by the main text, beginning directly with the verb, in both the inner and outer script, e.g. [ἔχει name <nom.>], [764; 767]. Symbola display a [ὁμολογεῖ + infinitive] construction, e.g. [ὁμολογεῖ name <nom.> ἔχειν] [1765 252 BCE, Philadelphia], or [ὁμολογεῖ name <nom.> μεμετρῆσθαι] [1832 257 BCE Philadelphia]. Two Oxyrhynchite receipts with a subjective construction refer to themselves as symbola: ὁμολογῶ ἠγορακέναι ‘I agree that I have bought’, [4339 l.8-9, 245 BCE; 4340 l.12, III BCE κατὰ τὸ σύμβολον τοῦτο ‘according to this symbolon’].
Receipts issued by naukleroi have a very brief inner script comprising a short date and the amount of grain transferred, whereas the outer script may have a longer (but not full regnal) date, and the construction [ὁμολογεῖ name <nom.> (ναύκληρος) ἐμβεβλῆσθαι] ‘I Nnaukleros agree (that x amount of grain) has been loaded’ [3066; 5071 152 BCE, both Arsinoite nome].
Double documents are found in a transversa charta format, with the writing against vertical fibres, e.g. [5838; 2796 173 BCE, Krokodilopolis] and in this orientation with the writing along horizontal fibres, e.g. [56; 78]. They appear in pagina format with vertical fibres [2674; 2666 215-214 BCE, Oxyrhynchus], and with horizontal fibres [2946; 3097]. Some documents can be quite wide, e.g. [95: H.15.2 x W.58.4cm; 84: H.14.6 x W.63.5cm; 78: H.15 x W.63.5cm], and some quite long, e.g. [2946: H.32.3 x W.10cm; 5837: H.51 x W.40.5cm]. Some receipts are long and narrow, typical of the demotic format [762: H.30 x W.7cm; 1832: H.33 x W.9cm (with demotic subscription), both 257 BCE, Philadelphia], see [Sarri 2018 : 95-97].
Double documents are written out twice on the same sheet with a space between the inner and outer script to facilitate rolling from the top [3100; 5768 75 BCE, Arsinoite nome], or from the left hand side , enclosing and sealing the inner script. There can be another space left between the end of the text in the outer script and any subscriptions . As the outer script may have been written before the inner script, the latter can be cramped into the space allowed [2946; 44733]. The whole document can be presented in a single column [44733; 2063] or two  or more [13; 56 (three columns); 131 109 BCE, Pathyris (four columns)].