Historical background and description
In 1900, Adrien Blanchet published the first systematic discussion of 3rd century CE Roman coin hoards. According to him, the coins were deposited when Germanic tribes invaded Gaul; to preserve wealth in the face of danger, people buried their savings. Blanchet’s work was extremely influential in the development of Roman hoard studies in the 20th century, to the extent that every hoard found since then has been associated with threats of violence, even if they are not recorded in historical sources. This principle is still influential in modern hoarding studies in Britain, where scholars try to pinpoint the advance of historical armies based on the locations of coin deposits.
However, critics have pointed out that we also possess large quantities of coin deposits from regions and periods in which there was peace and stability. Furthermore, identifying deposits as emergency hoards assumes that Roman coins were perceived invariably as valuable money and therefore represent the storage of monetary wealth, a perception with which not everyone agrees. Thus, the interpretation of any coin deposit as an unretrieved emergency hoard must be scrutinized carefully. What we can say is that this kind of deposit was created on impulse rather than careful planning: one did not deliberately select certain types, but took whatever was on hand when the crisis arose. Thus, emergency hoards will usually be heterogenous in variety but homogeneous in date range, reflecting the coins in circulation at the time of deposition (creating a numismatic “snapshot”). Emergency hoards were also meant to be retrieved: they were placed in accessible spots and archaeologists are only able to find them when something happened to the owner that prevented him or her from returning.
I believe there are six qualities an ancient synagogue deposit should have to recognize it as an emergency hoard:
1) The coins are found together as a group (they were often placed in a container, to make retrieval easier),
2) the deposit displays the full range of denominations that were in circulation at the time of a threat and were being used as functional currency, but the deposit may contain low value and high value coins, depending on the wealth of the owner,
3) the deposit shows a narrow date range, as the owner took what was on hand,
4) there is no evidence that coins were selected for certain types or emperors, and both new and worn coins are represented,
5) the deposit was hidden with the aim of one day being recovered and thus may contain other personal items of value (like gems and jewelry),
6) and an emergency deposit is “closed,” placed in a hidden location where it could not be found by outsiders, but easily retrievable by the owner or others.
Why the synagogue was chosen to hide coin deposits is unknown, but perhaps it was considered sturdier than a normal house and could be locked, elevating the chances that the building would survive a riot; the building could have been considered a sacred and safe place to protect the money; and there were more safe hiding spots such as under the stone flooring or inside the bemah where the money could have easily been retrieved if the building was destroyed. People might also have seen the synagogue as a holy place in the sense that it is specially protected by God and robbing it would be a particular sacrilege.
Deposits categorized as emergency hoards
Based on the qualifications set up above, I suggest that the following six synagogue deposits may fall under this category: Qasrin (Deposit 2), Korazin (Deposit 4), Horvat Kur (Deposit 3), ‘En Gedi (Deposit 2), Ma’oz Hayyim (Deposit 1), and Rehob (Deposit 2). A map can be found at https://www.ancientsynagoguecoins.com/emergency-hoards/ .
At Qasrin, 84 or 85 bronze coins (folles and half-folles) were discovered over the course of the excavations along the southern wall of the synagogue hall, close to the northeastern corner of a platform built against this wall. 82 of these coins were found grouped together probably below the plaster floor of the building, although at the time of its discovery, no attempt was made to establish the deposit’s stratigraphic relationship to the synagogue floor. Three additional coins were found in close proximity to the deposit during separate excavations, and these have been added to the final deposit count. Two of the coins come from a matrix of small stones and compact earth that acted as foundation fill below a pillar base placed in the plaster floor next to the platform. This plaster floor is a replacement of an earlier mosaic floor, and it is possible that the coins originally were placed under the mosaic floor and not the later plaster floor. Although no container was found, the coins were not scattered but clustered in one place, and in good condition: it is thus possible that they were deposited together in a perishable container. No coin deposits were found below the floor in other parts of the synagogue. Over 400 bronze coins were found in a building north of the synagogue at Korazin, separated by a corridor. This building, labeled Building E, also contained a miqveh. The coins were found inside a natural water channel covered by stone beams. Eight gold coins were found under the eastern stylobate bench of the synagogue at Horvat Kur. These coins were discovered close to and below two large stone blocks next to each other that made up a bench dividing the main hall from the eastern side aisle (but above the plaster floor on which the bench sat). Under the southernmost block, a lead vessel was excavated as well, which had two of the coins lying next to it. The excavators assume that all eight coins originally came from the same deposit.  At ‘En Gedi, 41 Byzantine folles were found wrapped in cloth, placed in an oil lamp, and hidden underground, in a courtyard just outside the synagogue. At Ma’oz Hayyim, a clustered deposit was discovered just outside the apse, next to the synagogue building.  This deposit consisted of 48 gold coins, wrapped in a piece of cloth and placed under a broken roof tile. These coins were never published but are located at the IAA. Last, at Rehob, archaeologists found 14 Arab-Byzantine bronze coins, apparently wrapped in cloth, beneath the rubble of a collapsed wall separating the western aisle from a small room west of the bemah.  The coins have not been published yet.
All the coins from these deposits were found in clusters, wrapped in cloth or other materials, and stored in places that were easily recognizable, and thus easy to remember: in a water channel, under a decorative stone, right outside the protruding apse, etc. However, half of our examples (Korazin, Ma’oz Hayyim, and ‘En Gedi) were found not inside but in close proximity to the synagogue: this might indicate that emergency hoards were not normally buried in synagogues, but that scholars have mistakenly associated these deposits with synagogue activities. Perhaps these three examples should no longer be mentioned in connection to ancient synagogue coin deposits.
As for dating the different deposits, they all seem to belong to different, but late, periods. The terminus post quem of the deposit of Korazin is the fourth quarter of the 5th century (498 CE), of Horvat Kur the fourth quarter of the 6th century (584 CE), of Qasrin the first quarter of the 7th century (608 CE), and of Ma’oz Hayyim and Rehob the fourth quarter of the 7th century (696 CE and 690 CE respectively) (https://www.ancientsynagoguecoins.com/emergency-hoards/). More research into the historical context of these periods in the future might be able to connect the deposits to specific crisis events.
Map of all sites where Emergency Hoards have been found. Hover over a triangle to see the name of the site.
Table of all Emergency Coins broken up per deposit. Toggle the parameter to show the emperor under which each coin was minted, the minting place, or the end date (final terminus post quem) of each coin.
Table of all Synagogue Emergency Coins. Toggle the parameter to choose between exact dates or quarter centuries.
Table of all Synagogue Emergency Coins. Toggle the parameter to show the emperor under which each coin was minted, the minting place, or the end date (final terminus post quem) of each coin; or choose between absolute numbers or percentage of total.
 Blanchet 1900.
 See for example, Crawford 1983; Aitchison 1988.
 For a good introduction to emergency hoards, see Curta and Gândilă 2012.
 I believe that most emergency hoards would have been buried or hidden inside the owner’s house (see the debate on ‘En Gedi, Deposit 2). Here, however, I am looking at deposits discovered in synagogues to see if any might have been emergency hoards. See also Avi-Yonah 1981; Tzaferis 1981; Ilan and Damati 1987.
 This is perhaps the weakest quality, as people could also hide their personal savings, which they had stored in their own house for decades. However, the narrow date range of emergency coins has been discussed by Waner and Safrai in their study on the “shelf life” of coins in ancient Palestine hoards (Waner and Safrai, 2001).
 Of course, houses could also be locked, especially if the owner was wealthy.
 Think, for example, about the storage of valuable items in churches and synagogues during WWII.
 This assessment has been made on the assumption that the deposit was indeed found in a water channel, and that this channel was connected to the synagogue. If, however, the coins were found in a “specially cut chamber” as Yeivin first claimed in 1987, I would place this deposit under the treasury category. If the room cannot be connected to the synagogue, we should delete this deposit from our overview.
 This deposit could also be interpreted as a magico-religious deposit or a treasury (as Zangenberg, Rheeder, and Bes forthcoming state). However, the fact that the coins were grouped together, low in number, inaccessible, and all from the same period, makes me think it is a (communal, seeing the effort it would take to lift the stone) emergency hoard (perhaps originally part of the community treasury but stored here for safekeeping?).
 Again, this interpretation has been made on the assumption that the courtyard was connected to synagogue complex.
 Same remark as ‘En Gedi. I still believe this is an emergency hoard, but it might not have been connected to the synagogue and its functions.
 Since this deposit, including its archaeological context, has not been published yet, this is an educated guess. The fact that the coins date from the period just before the synagogue was destroyed and were wrapped in cloth makes me think it was an emergency hoard.
 Reasons, for example, could have been Persian attacks on the region between 540 and 562 CE; continuous waves of the plague (Ariel 2002, p. 299; Ahipaz 2007, p. 162); the Samaritan revolts of 484 and 529 CE; the Persian invasion of 614-615 CE (Ariel 1996, p. 69); and the power struggles over the caliphate in the 680’s, which can be discerned in a clear rise in the concealment of hoards in Syria-Palestine (Walmsley 2007, p. 324). Of course, as mentioned earlier, the need to assume that each hoard was created in light of a public crisis might not always be correct. Some emergency hoards could have been made because of personal fears, like hiding money from a debt collector or estranged family.