“There is no proof whatsoever that those nails came from the cave of Caiaphas. There is no proof that the nails are connected to any bones, or that there is any bone residue attached to the nails. There is no proof from textual data that Caiaphas had the nails from the crucifixion with him after the crucifixion took place and after Jesus was taken down from the cross.

(Prof. Gaby Barkai, Telegraph, UK, 12 April, 2011).”

Such lofty declarations and academic disputes pertaining to the Caiaphas family tomb and two (arguably) crucifixion nails found therein have in major part been confined to the media and scholars in the fields of archaeology, anthropology and divinity. Besides the excavators few, if any, have examined or studied the ossuaries from the Cft (Caiaphas family tomb) and certainly not the nails above, was of adequate merit to inspire the scientific efforts below. Although the route following the present endeavours is rather lengthy we trust that what we here view as an original contribution not only to scientific thought of artifacts discovered in ancient ossuaries but also to Christianity at its very earliest, do these efforts justice.

What is referred to as the Caiaphas family tomb was discovered by construction workers in 1990 in the Jerusalem neighborhood of North Talpiyot, located about halfway between ancient Jerusalem and Bethlehem (Figure 1). The Cft is one of three tombs located within ~200 meters and less of the Lower (Hellenistic period, 1^st - 2^nd century BC) aqueduct with (arguably) all displaying some evidence of early Christianity (Tabor and Jacobovici, 2012; Shimron et al., 2020). The Cft was broken into by tomb robbers, probably during the Byzantine period. Except for Ossuaries 5 and 6 which were found in their kokhim with their lids on, all ossuaries were moved from their rock shelves (Greenhut, 1992, 2004) at this time. Ossuaries 1, 2, 3, and 4 were found whole whereas six additional ossuaries were found shattered but were later reconstructed by the Israel Antiquities Authority (IAA). A total of 12 ossuaries were removed from the tomb during the archaeological excavation. The exterior walls of five ossuaries are inscribed, and six are decorated with floral motifs, Ossuary 6 magnificently so ( Greenhut , 1992 ,Figure 2(b)). The name “Caiapha” is inscribed on the latter and also on Ossuary 3. A coin of Herod Agripa 1 from the year 42 - 43 CE was discovered in the scull inside Ossuary 8, besides precisely dating the tomb it also points to the pagan custom of placing a coin between the teeth of the deceased as payment to Charon, the ferryman in Greek mythology (Toynbee, 1971) thus pointing to the usage of this pagan custom in Jewish Jerusalem during this period (Hachlili & Killebrew, 1983; Tabor & Jacobovici, 2012). Most scholars agree with the excavators that the inscribed names refer to the family of the 1st century CE Jewish high priest Kaiapha, transliterated “Caiaphas” in the New Testament.

Two iron nails were discovered during excavation of the tomb (Greenhut, 1992), one on the floor of the southern loculus (kokh IV) in which ossuaries 5 and 6 were contained, the other, according to the head excavator (Greenhut, 2004) inside Ossuary 1. Regarding the function of the nails, Rahmani (1961) suggested that nails found in tombs were used for fixing ossuary lids or for scratching the name of the deceased on an ossuary’s side. This interpretation remains prevalent and is thus far the only opinion expressed in academic circles. Consequently, the official IAA statement that the nails uncovered in the tomb during its excavation were misplaced or transferred to some unknown location did not cause any clamour.

About 20 years ago, Prof. I. Hershkovitz of the Sackler School of Medicine and Anthropology laboratory at Tel Aviv University received from the IAA two small boxes. One box was clearly marked as originating from the laboratory of the late Prof. Nicu Hass; the other box, which held two nails, was unmarked and the provenance of the nails that it contained was not specified. The two boxes were stored in the laboratory’s safe. A few years ago Prof. Israel Hershkovitz showed them to journalist Simcha Jacobovici who, based on his investigation of the Caiaphas family tomb finds, hypothesized that the two unprovenanced nails in the unmarked box were the missing nails from the Cft (Jacobovici, 2014). He further surmised that, given their morphology, these nails may have been used in a crucifixion and furthermore, in view of their archaeological context (tomb of the high priest Caiaphas) the crucifixion may have been that of Jesus of Nazareth. Thus far the only unambiguous physical evidence of nails used in a crucifixion is the 11.5 cm long Heel Bone nail from the crucifixion of Yehohanan Ben Hagaol discovered in a Jerusalem tomb in 1968. The gravity of these implications have led us to carry out the present in-depth scientific investigation of materials in the Caiaphas tomb ossuaries and also of the two unprovenanced nails from Prof. Hershkovitz’s laboratory. Such a geochemical-petrochemical study of provenancing materials excavated from tomb ossuaries has, to the best of our knowledge, only one precedent—our recently published study on the ossuaries and materials from the nearby Talpiot—“Jesus family” tomb ( Shimron et al., 2020 , and Figure 1).

Sampling of sediment flushed into the Caiaphas tomb ossuaries was carried out by technician Oded Reviv of the IAA. A few grams (about 1 - 2 teaspoonfuls) of loose sediment and/or fine rubble were collected from ossuaries 1, 3, 6 and 7 (a repaired ossuary) using a stainless steel spatula. Occasionally this was not feasible, in such case, sediment was scraped off from the ossuary bottom and/or ossuary walls (laminated wall crusts) with a stainless steel scalpel. Grain mounts for the scanning electron microscope (SEM) and polished and regular thin sections for study in transmitted light optical microscope were prepared from fine materials. The two unprovenanced nails were sampled in the laboratory of the Dept. of Anthropology, Tel Aviv University. This was carried out by the senior author (AES) using a specially prepared stainless steel holder on which a small diamond bit was mounted. As sampling small artifacts is a destructive process only a small amount (maximum 1/4 teaspoonful) of rusted iron and carbonate carapace could be scrapped off from the oxidized surface of each nail. These materials were studied under the petrographic and scanning electron microscope and analyzed by SEM-EDX, X-ray diffraction (XRD) and δ¹⁸O and δ¹³C isotopic analyses. Prior to the above studies, the nails were examined and photographed intact under low power SEM magnification.

X-ray diffraction analyses were done at the geochemical laboratory of the Israel Geological Survey using a Philips XRD diffractometer with the following equipment: 1. High tension generator—PW1830 operated at tension of 40 KV and a current of 30 mA, 2. Philips MPD control—PW 3710, 3. Philips Goniometer—PW 3020, operating with a Cu long fine focus PW—2773/00 target, 4. Slit system: divergence slit—1˚, 5. CuKBß radiation was eliminated with the aid of a Philips PW 1752/00 Monochrometer. The <200 mesh ground samples were inserted in the diffractometer in a standard Philips rectangular aluminum sample holder.

Scanning Electron Microscope (SEM-EDX) analyses were carried out at the Hebrew University Nanolaboratory (The XPS Laboratory Unit for Nanocharacterization, The Harvey M. Krueger Center for Nanoscience and Nanotechnology in Jerusalem) by Dr. Vitaly Gutkin (supervisor of the unit) and AES—the senior author. The scanning electron microscopy images were obtained using an FEI Quanta 200 ESEM in low-vacuum mode without any preliminary treatment and with a chamber pressure of 0.38 Torr and acceleration voltages of 15 - 20 kV. Elemental analyses were carried using EDX (Energy Dispersive X-Ray spectroscopy). Energy Dispersive X-Ray Spectroscopy is a chemical microanalysis technique used in conjunction with SEM. The EDX technique detects X-rays emitted from the sample during bombardment by an electron beam to characterize the elemental composition of the analyzed volume. All photos used in this manuscript, unless denoted otherwise, are SEM micrographs.

Stable isotope δ¹⁸O and δ¹³C measurements were performed using a Gas Bench system attached to a Delta Plus mass spectrometer (Thermo). All δ¹⁸O and δ¹³C values were calibrated against the international standard NBS-19, and are reported in permil (‰) relative to the VPDB standard. Analytical reproducibility of duplicates is better than 0.1‰ both for δ¹⁸O and δ¹³C.

Burial tombs are cave-like features and the ossuaries therein act like small caves within a larger one. An ossuary is a box generally constructed of local stone, in Roman period Palestine soft local chalk and limestone were the favored construction materials. Ossuaries were the final resting place of human skeletal remains containing a single or occasionally more skeletons. During burial, a body was first placed on a temporary rock ledge inside the tomb from which, after about one year, the bones were removed and placed inside an ossuary. Besides the skeletal remains, natural materials inside tomb caves are weathered and disintegraded local stone to which varying amounts of soil and organic matter were subsequently contributed by the incursion of water during seasonal winter rains. Periodically, added to this mix was aerosol—a mix of wind-carried fine particles of comminuted rock (mostly well-polished quartz micro-grains) and soil with additions of local organic materials. Soils in major part develop by weathering of local bedrock, in West Jerusalem this is Turonian age limestone, dolomite and more rarely clayey shales producing Terra Rossa soils. In South and East Jerusalem (the hill tops and eastward toward the Rift Valley) White Rendzina soils (Table 1, An. 41) overlie Senonian age chalk and chert bedrock. The specific location of the Caiaphas tomb ~50 meters directly downslope beneath the Hellenistic period Lower aqueduct, appears to have played a significant role in the geochemical evolution of the tomb and ossuaries by periodic contributions of moisture from water overflow in the aqueduct.

Optical microscope, and SEM examinations and eventually XRD analyses showed that much of the bone components in the ossuaries suffered degradation, micritization and recrystallization. For a climate entirely dry for about seven months of the year, more than the usual amount of moisture must have periodically entered the Cft ossuaries. This is well shown by a discreet wall and floor-parallel millimeters-thick internal lamination of fine sediment mixed with decayed bone rubble containing small amounts of other organic materials. It is particularly well manifested on the walls of Ossuary 6 (Figure 2(a)) as a white chalk (ossuary construction material) substratum (a) covered by a pale brown clayey soil layer (b) in turn covered by fine layers of lumpy phosphatic crusts (c) finally capped by a veneer of white carbonate flowstone carrying much aerosol quartzose dust (d). The vertical wall layers formed during fluctuating water level inside the ossuary and accretion onto the walls of fine sediment floating on the water interface. The ossuary floor (e) exhibits a similar horizontal micro-lamination with individual floor laminae of detritus carrying soil, micrograins of quartzose aerosol (Figure 3(a)), degraded bone and finally flowstone. Bone degradation was accompanied by crystallization of fluorapatite [Ca₅(PO₄)₃F, Table 1, Figure 4] and hydroxyapatite [Ca₅(PO₄)₃OH]. Small grains of anhydrite, gypsum, barite and chips of iron oxide (Figure 3(b), Table 1, An. 12, 16) are also present.

We refer to the two nails studied as Nail 1 (white carbonate head) and Nail 2 (white carbonate lower body). The nails are 8 cm long with a slightly tapered end, they were purposely bent at an angle of 65˚—on Nail 1 and 75˚—on Nail 2 (Figure 8), a practice apparently linked to nails used in crucifixions. The white fragments attached to the Aba and Yehohanan nails (bottom right) are mostly secondary phosphate minerals formed from the decay of bone phosphorus. The external crust of metallic iron of the nails is now entirely converted to micro-laminated orange to reddish-brown to almost black-colored iron hydroxides (Figure 7(d)). Some of the lamina are rich in concentrically zoned spheres (botryoids above) which, if organic in origin (Table 1, An. 30 - 32) may suggest that bacterial Fe (II) oxidation by (iron-eating) microorganisms (Casanova et al., 2010) may have played a role in the conversion of metallic iron to iron oxide. We emphasize that amongst the phosphatic floor debris of Ossuaries 6 and Ossuary 1 we found a number of fine chips of iron oxide with FeO concentrations reaching 83.5% (Figure 3(b) and Table 1, An. 12, 16).

Fine fragments of iron oxide and separately from flowstone carapace were scrapped off the nail surfaces and studied under the optical transmitted light microscope, SEM and by XRD. During oxidation of the nails, the metallic iron was converted to finely laminated brown to reddish colored iron hydroxides goethite (α goethite) and the uncommon lepidocrocite, a dimorphous form of goethite (γ goethite, Figure 9), both with the chemical composition FeO(OH). Although the amount of lepidocrocite is close to equal on the two nails the goethite polymorph comprises ~44% on Nail 1 (white head) and ~67% on Nail 2. A small amount (~1.6%) of magnetite crystallites are present on Nail 1 but are not present on Nail 2 (Figure 10(a), Table 1 An. 28, 29). The magnetite is present in perfectly shaped rhombic dodecahedra and cubes ~4 μm in size; the crystallites define the final phase of iron oxide crystallization on the nails. In contrast to the hydroxides lepidocrocite and goethite the late-stage magnetite (Fe₃O₄) crystallized in what, at that time, was an anhydrous environment.

We were amazed to discover, even under low power SEM magnification, ~2 cm long fine slivers of wood accreted to both nails buried within quartzose sedimentary debris. Many of the wood cells are entirely filled with radiating fibers and blades of crystalline iron hydroxides (Figure 13(a)). In addition, we also found in the ferruginous debris and within the wood tracheids (cells), small—yet very pronounced amounts of organic materials all of which we have also identified in the tomb ossuaries. They include chips of micro-bone, fungal sporangia, at least two dominant forms of spores and related filament tubes such as sporangiophores and hyphae (Figures 12-16). Near concentrations of organic debris we have noted (SEM-EDX) an occasional pronounced increase (0.2% - 0.57%) in phosphorus concentration (e.g. Table 1, An. 36, 37), a feature especially noted on Nail 2. We attribute such anomalous phosphorus concentrations to the presence of bone tissue now, as shown above, in major part decayed or replaced by iron oxides (Figure 11, Table 1 An. 35, 39). It is amazing how the organic components of the wood, including all the invasive and/or accreted biological species have, as the wood, been entirely converted to iron hydroxides. A similar phenomenon, a “pseudomorphous” replacement of coffin wood cells by iron corrosion products adjacent to iron bars inside an 8^th century BC tomb at Gordion, Turkey, was observed by Blanchette and Simpson (1992). We consider such complete replacement of the wood organic components by iron hydroxides as a petrification process, in the sense that the mobile iron replacing the organic compounds was controlled by the wood and fungal microarchitecture on an atom by atom basis.

One of us (WHS) identified the wood to be that of a mature Cedrus (Cedar)—a genus of coniferous trees in the plant family Pinaceae. In the Mediterranean region Cedar occurs at altitudes of 1000 - 2200 m and although an important tree in the mountains of Lebanon (Cedrus Libani), Syria and Turkey it was a special and costly, perhaps even extraordinary, import into Roman period Palestine. The present identification is based on detailed SEM study of some well preserved morphological features which characterize Cedar wood. They include the width of latewood zones, decorated tori, rays of parenchyma cells with taxodioid pits, heterocellular rays and resin canals, features we show below (Figure 13, Figure 14, Figure 16(a)).

During our study of the Caiaphas tomb ossuaries and the two unprovenanced nails we discovered evidence of widespread microbial infestation accompanied by partial biodeterioration of organic components in both the ossuaries (bones) and also of the wood accreted to the nails (above). Bone and wood provided a choice habitat for microbial attack and both were colonized by what appears to be a single species but it is feasible that in view of the ~1900 year time span, more than a single generation and species of fungi is manifested. The fungal morphologies include (Figures 15-17) round to occasionally oval microstructures most of which constitute fungal sporangia. The sporangia are enclosures in which spores—the fungal reproductive cells—are formed and from which they eventually are forcefully expelled before proceeding to the next evolutionary step of germination. The sporangia and germinating spores often exhibit protrusions of filamentous tubes (sporangiophores or hyphae)—the main mode of vegetative growth of fungi which function as conductors transporting water and other nourishment from roots to leafs of growing plants. The spores when released from their housing into the air are dispersed by wind and water and can travel great distances from their source.

Fungal activity inside ossuaries will result in partial to complete degradation, or chemical breakdown, of bone microstructures and, if present, the wood cell network. In the latter case, decay attacks the primary cell wall components—the carbohydrates, lignin and cellulose, a process accompanied by the release of CO₂ (Figure 13, Figure 19 and Table 1, An. 33). We have observed two (but not only) principal varieties of spores in our materials (1) a group of small spores ~3 to ~4 μm (0.003 to 0.004 mm) in size and (2) a second group ~8 to ~10 μm in size, with some marked exceptions (e.g. Figure 19(b), Figure 20(a)) noted. We will herewith refer to the former as Ss (small) spores and the later as Sg (germinated) spores, the former (Ss spores) resemble a tightly clustered mass of globules or clusters of grapes, the latter (Sg spores) occur as individuals or small bunches of ~5 - 10, frequently pear-shaped bodies. The Ss spores are very much dominant inside the ossuaries where they have colonized the microstructures of bones but also other organic (e.g. insects, Figure 17(b)) morphologies. The Sg spores, although also present inside degraded bone microstructures, are ubiquitous inside the wood tracheids, which was clearly their much preferred habitat. Because of the close spacial relationship and presence of what appear to be transitional stages between the two spore groups (e.g. Figure 19 and Figure 20(a)) we reason that rather than what at first glance appear to be different fungal species they are one species in different stages of development leading to germination. We emphasize that some of the spore-like structures reveal an internal microfabric resembling yeast cells (Figure 16(b)). Spores are unicellular, but under favourable conditions, which involves an exogeneous supply of moisture, water and nutrients will germinate, a process that entails spore swelling and change in shape and finally extrusion of one or more germ-tubes (Figure 18(a), Figure 19(a)). Microbial degradation is affected by amount of light, water and oxygen availabilty, it will take place as the hyphae spread through food and release enzymes that break food down into substances that the fungi can easily absorb. In Figures 15-20, we have tried to elucidate some of these processes and the range of fungal micromorphologies that we have encountered in the ossuaries and nails (Full explanations in: http://www.fungionline.org.uk/).

Surface rain waters percolate downward through soil and by reacting with CO₂ supplied by biological activity form carbonic acid (H₂CO₃). The acid reacts with the host rock and the water becomes saturated with respect to calcite forming Ca(HCO₃)₂ in solution. Should the water reach the open space of caves (or tombs) under certain conditions CO₂ degassing will take place and carbonate minerals will be deposited as speleothems or flowstone (stalactites, stalagmites). Chemically what takes place is the compound Ca(HCO₃)₂ breaks up to CaCO₃ (flowstone) + CO₂ + H₂O. In their study of some Israeli caves Bar-Matthews & Ayalon (2001, 2004) amongst others, have shown that the oxygen isotopic composition (δ¹⁸O) of speleothems reflects the temperature at the time of their deposition and also the δ¹⁸O values of the water from which they were deposited. In another study, performed to evaluate the rain shadow effect on the amount of rainfall and speleothem growth, Vaks (et al., 2003) found that variations in the carbon isotopic composition (δ¹³C) of speleothems results from differences in the type of vegetation in the vicinity of the cave. In such a case, enrichment in the δ¹³C (seen in lower negative values) of calcite speleothems usually reflects an increase in the contribution of C4-type plants (crop plants, saltbush, corn, annual summer plants) to the soil CO₂. We know that the sudden passage from the western to the eastern (rain-shadow) side of the Jerusalem mountain ridge is highlighted by an increase in temperature and evaporation rates, in addition to being accompanied by a sharp drop in rainfall from ~500 to 250 mm (Vaks et al., Figure 1). Notably, these features are also manifested by an increase in δ¹⁸O and δ¹³C (lower negative) vaues. On the basis of these data, it has been concluded that the δ¹⁸O and δ¹³C isotopic composition of speleothems is dependent on environmental conditions.

The Ma’ale Efrayim Cave is located in the rain shadow on the eastern side of the central mountain ridge on which Jerusalem is located. The Soreq Cave is located in the rainier western side of the mountain ridge whereas the Jerusalem West Cave (Frumkin et al., 1999) lies close to the central part of the ridge, near the heart of the city. The Caiaphas family tomb lies about 7 km directly south of the Jerusalem West cave about halfway between central Jerusalem and Bethlehem. It is located on the east-facing slope of the Jerusalem mountain ridge, just within the western edge of the “rain shadow” desert region (ref. above). We show and compare our δ¹⁸O and δ¹³C values with data from flowstone collected from the caves above (Table 2, Figure 21). We note that the δ¹⁸O and δ¹³C values we obtained for Ossuary 6 and Nail 1 are (1) very similar and (2) considerably closer in magnitude than values obtained from the same speleothem for different periods in time in the caves above. The Nail 1 value is close to Jerusalem West cave present values. Isotopic δ¹⁸O and δ¹³C values oscillate frequently with time and up to 2.15‰ variation within a single annual growth band has been measured, consequently, the small difference in the isotopic values of Nail 1 and Ossuary 6 is insignificant and can be attributed to a slight difference in time of speleothem deposition. We conclude that our δ¹⁸O and δ¹³C values are 1) higher than almost all values for the last ~5000 years obtained for flowstone from Jerusalem area caves and 2) it appears that waters from an area rich in C4-type plants made a higher contribution to the Caiaphas tomb and Nail 1 isotopic values than those from other caves sampled. Such data make the Ossuary 6 and Nail 1 values unique.

The Ossuaries: The IAA has not reported two nails found or missing from any excavation other than those from the Caiaphas tomb. Nonetheless, we have examined the possibility that the unprovenanced nails were derived from another tomb where bioactivity by species identical or similar to those in the Caiaphas tomb had taken place. For this and other objectives, we have sampled and studied the petrography and petrochemistry of materials from interiors of about 40 ossuaries collected from some 25 tombs in the Jerusalem area ( Shimron et al., 2020, Figure 1). We can now conclude that we have not found any fungal or bacterial species or biodegradation of the type we observed in the Cft and on the two nails, in ossuaries from any other tomb. In addition, neither have we found evidence or any record of such profuse and continuous flooding of ossuaries from any of the other tombs that we have examined. We reason that a continuous abundance of water and colonization of the tomb by a unique fungal species makes the Cft and materials found therein so profoundly unique. Besides winter rains the amount of moisture in the Cft was influenced by periodic water overflow from the neighboring Hellenistic period aqueduct. Wall-parallel laminae of sediment and bone rubble with various degrees of bone degradation and decay are testimony that geological and biochemical processes were periodically active in the ossuaries. The stone boxes with bones, two with oxidizing iron nails with attached wood in standing pools of water must have been magnets for robust fungal activity. Bone degradation, wood decay and the character of the nails’ Fe-oxidation products testify on the dependence of their immediate environment on the amount and pH of standing water. We have shown that changes in bone micro-architecture seen in fragments of phosphatic crusts attached to the walls and floors of the ossuaries exhibit various stages of degradation, decay and recrystallization to fluorapatite [Ca₅(PO₄)₃F] and hydroxyapatite [Ca₅(PO₄)₃OH]— the expected and thermodynamically stable phosphate minerals that form under ordinary cave conditions (Trueman et al., 2004 and Table 1).

Although Ossuary 6 was found in situ, its cover was removed by Byzantine-period tomb robbers only to be replaced shortly thereafter perhaps out of respect for the recognizable inscribed Caiaphas family name. The ossuary was not moved by robbers from its original site for the same reason and the only disturbance it may have suffered is the removal and immediate disposal of a nail (Nail 2) found by excavators on the kokh floor near the ossuary. In the first excavation report the head excavator (Greenhut, 1992) notes that “one nail was found inside one of the ossuaries” while the other on the floor of Kokh IV (that is near Ossuary 6). In a subsequent report Greenhut (2004) however notes that one nail (Nail 1) was found in Ossuary 1. In the present work, we have assumed that the latter report is accurate and that indeed one of the two nails (Nail 2) was removed from Ossuary 6 during the robbers’ incursion into the tomb whereas the second nail (Nail 1) spent its entire ~1900 year long history undisturbed inside Ossuary 1. We have summarized our main observations and elucidate the main links between the Cft ossuaries and the two nails in Table 3 below.