For this undertaking, a digital database of all sites, deposits, and coins was created in Microsoft Excel, under the guidance of Will Bosley from the University of North Carolina Digital Innovation Lab. Maps, analyses, graphs, and tables were then made in Tableau, an interactive data visualization program, under the guidance of Lori Bruckner from the UNC University Library. The advantage of utilizing these programs is that they can handle the storage and retrieval of large amounts of information without loss of quality or data redundancy (so-called “big data”). It also makes it easier and much faster to recover data, apply queries, and visualize patterns within the data assemblage. The graphic representation of the data – whether geographical information shown on maps, temporal data shown on timelines, interpersonal relationships shown as connected graphs, etc. – allows users to comprehend the information quickly and helps them to manipulate and analyze the data according to their own questions.
The most difficult task when creating any database is determining its types, categories, and entries. These parameters are generally determined by the objectives of the research itself: what are the questions one needs to ask to get the answers one seeks? For my database, five layers of information were created, each “zooming” deeper into the research material. As Microsoft Excel is widely accessible, free of charge to students, and easy to navigate, I chose to build the foundation of my database with this tool. Thus, each layer of information was assigned its own spreadsheet in which I created tables. The first layer is labeled “country.” Here I entered the countries in which synagogue deposits have been found. As my research focuses on modern Israel/Palestine, this forms the bulk of my list; the two other countries are Italy and Turkey. The second layer is the “site.” Here the name of the site where the synagogue building was found is given, together with its longitude and latitude coordinates. This enables Tableau to place the sites on a self-generated map. The third layer is the “building” layer. In this layer, I made a different row for each building phase of each synagogue in which a deposit has been found. For example, we know that the synagogue of Horvat Rimmon had three distinct phases. For each phase, I noted its construction date and a brief description of the lay-out of the building in that phase. This is necessary to connect a certain deposit to a certain phase of the building. For the building as a whole, I noted its date of discovery, the archaeologist(s) who excavated it, and as complete as possible list of bibliographical notes. The fourth layer is the “deposit.” Sometimes multiple deposits were discovered in the same synagogue building and needed to be differentiated. I noted the exact find spot of each deposit within the building, both in a long description (“Deposit found under the floor in the north-eastern corner of the courtyard of the synagogue of Capernaum”) and a short one (“floor”). The short description allows Tableau to generate groups of deposits found in similar contexts across all buildings. I also noted whether the specific context had received any kind of archaeological legend in the publications (for example, “Area 12; Trench XII; L812”). Then I recorded in what year the deposit was discovered with a full description of the deposit and its context. I endeavored to provide as complete a description as possible, as deposits sometimes have been published in a fragmented manner in different excavation reports. My goal was to, for the first time, bring together all the information we have on each deposit and its archaeological context. I mostly based these descriptions on the published material, but I also contacted as many excavators as possible to discuss their finds and acquire additional, hitherto unpublished information. When archival materials were available to me, I explored these too. I also noted if the deposit was found in a container and if so, in what kind of container, and if the deposit was retrievable (as, for example, in a hollowed-out floor stone), or not (for example, when it was plastered into the foundation of benches). Last, I noted how many coins were found in the deposit and where they are stored now.
My last layer is my most elaborate one: the “artifacts” layer. This is where I zoom in on each individual coin found in a deposit. I organized this layer in the following way: each coin found in a synagogue deposit received a unique ID number. In total, I have information on 10548 coins. I organized the coins according to their deposit and gave each coin a specific number in their deposit (for example, “Coin from under the floor outside the threshold of the synagogue of ‘En Nashut (Locus 109): No. 1”). This will make it easier to refer to individual coins in future literature. If a coin is stored at the Israel Antiquities Authority (IAA), I also connected it to its IAA identification number. When a coin had received a different number in the publication report, I also noted that. Then, I provided a complete description of the coin, according to accepted standards. For each specimen, I indicated the emperor under whose reign it was minted, the date of minting, the denomination (if known and different from AE1, AE2, AE3, or AE4), the size and weight, and axis of the coin die, the material from which it was made, the minting place, and a description of the obverse and reverse sides split into inscription and image. These descriptions are coin specific and denote how much of the inscription and/or image could be read (for example, [GLOR-IA EX]ERC-ITVS, Two soldiers leaning on spears; between them one military standard. In exergue: illegible). If the coin shows other specific characteristics like graffiti or an overstrike, this is noted in the “Remarks” column. Here, I also noted the IAA photograph number if one exists. Last, I wrote down the coin catalogue parallel; that is, the specific catalogue book(s) in which this coin type can be found, the page, and the number. In the catalogue here provided, I also added a table for each deposit that illustrates the date range of the hoard as a whole, the emperor(s), and the minting place(s). These tables form small, easy-to-understand overviews of the deposits and help the viewer visualize the abstract data.
On the website www.ancientsynagoguecoins.com, which accompanies this written catalogue, each building, deposit, and sometimes coin has been illustrated with the appropriate maps, plans, drawings, photographs, or other archival materials that could be found. In each case, I have attempted to add at least one map of the location of the synagogue building within the town or city, a plan of the building that indicates the exact findspot(s) of the deposit, drawings of the building or certain important elements of it, and photographs of the building, coin deposits, and/or specific coins. Most of these images have been scanned from publications (for which permission has been granted) with a minimum resolution of 300 pixels but cannot be downloaded by third party users. In this regard the material is available for visitors to view but cannot be freely republished without permission from the excavators. Most of the images in this study have been published before (although they have never been brought together in one study), but some are new, and were provided to me either by the original excavators or were found at the archives of the IAA. What can be downloaded, though, are the spreadsheets with detailed overview of the analyzed coins per deposit. Scholars who are thus interested in the details of each specific coin can download my spreadsheets for free.
Compiling the database and building the website took over two years. I hope it will offer scholars who are interested in the field all the material they will need to investigate the synagogue coin deposit phenomenon further, without having to go through this process of tracking down the individual artifacts ever again.
 For examples of other coin databases and their methodologies, see Iossef 2016, p. 265. Currently, some of the best-known online coin databases include the UK Government’s Portable Antiquities Scheme (https://finds.org.uk/), Coin hoards of the Roman Republic Online (http://numismatics.org/chrr/), the online database of the American Numismatic Society (ANS) (http://numismatics.org/search/), and the Coin Hoards of the Roman Empire Project (http://oxrep.classics.ox.ak.uk/coin_hoards_of_the_roman_empire_project).
 As assessed by me, see “Difficulties in Dating Synagogues”.
 This type of organization is similar to the The Bornblum Eretz Israel Synagogues Website, a site whose goal it is to display the world of synagogues from the Land of Israel for the scholar, student, and layperson: https://synagogues.kinneret.ac.il/.
 For example, for excavations carried out in Israel before 1948 (then known as Palestine, governed by the British Mandate), I used the online Scientific Archives 1919-1948 within the Israel Antiquities Archives (http://www.iaa-archives.org.il/).
 See “Coins and how to properly excavate, publish, and read them”.
 See “Coins and how to properly excavate, publish, and read them”.
 Unfortunately, the IAA charges per photo requested. Because of the large number of coins in my database, it was not possible to include pictures of all the coins provided. Interested readers can contact the IAA and request prints.
 All data entry is prone to human error. I have tried to be as careful as possible when copying information but nonetheless, mistakes will have been made. I take full responsibility for incorrect information.
 The website was made by Melissa Stewart from the UNC Arts and Sciences Information Center, using Reclaim Hosting and WordPress. I could not have done this project without her help and I am grateful for her labor and support.
 Not all publishers granted me (online) publication of their images. For example, the Israel Exploration Society, which published excavation reports on multiple synagogues in this project, did not give me publication permission. These images are thus missing from the website.