Jericho chronology dispute

There has been controversy and dispute over the specific date of the fall of Jericho as recorded in the Book of Joshua in the Bible.

Debate over date of the fall of Jericho
In a 1990 publication (Wood 1990), archaeologist Bryant Wood argued that a proper study of the archaeological data, and especially the pottery evidence (his field of expertise) showed that the original date that John Garstang had postulated in the 1930s for the fall of Jericho City IV was the correct date. This ran counter to the opinion, fostered in the secular press and in most archaeological circles, that Garstang's date had been shown to be wrong by the subsequent studies of Kathleen Kenyon. Since the ongoing debate on this matter is relevant to questions of the veracity of the Bible, the historical background of the debate and its three principal protagonists follows.

Jericho: John Garstang
The article on British archaeologist John Garstang shows that he dated the destruction of Jericho City IV (the city level associated with Joshua) to the end of the 15th century BC on historical and archaeological grounds. He did not assume that the date which can be derived from Biblical texts was correct, thereafter adjusting the archaeological findings to fit the Bible. Instead, his assignment of the destruction by fire to around 1400 BC was derived from the following observations:
 * 1) Comparison of pottery in the destruction level with pottery from tombs that could be dated by Egyptian scarabs (Hatshepsut, Tuthmosis III, Amenhotep III) (1934: 107–10, 113–16; 1937: 1219, 1220; 1948: 121–27).  The two A III scarabs could have been placed in the cemetery by survivors who continued to make use of the cemetery after Jericho was destroyed.
 * 2) Scarab series on the tell and in the tombs ends with Amenhotep III (ca. 1386–1349) (1933:42; 1948:127).
 * 3) Lack of mention of Jericho in the Amarna Letters (mid-14th century) (1948: 126).
 * 4) Radical decrease in use of the cemetery after 1400 BC (1935: 63; 1948: 128–29).
 * 5) Lack of Mycenaean pottery which flourished in the 14th century BC, but not in the 15th century BC (1935: 65, 68; 1948: 126).

For further information on the evidence that led Garstang to date the fall of Jericho City IV to the latter part of the 15th century BC, see the John Garstang page.

Critique of Garstang's research
One place where Garstang was shown to be in error was his dating of a double city wall to the same time as Jericho City IV. The later work of Kathleen Kenyon showed that this double wall dated from a time some 1,000 years earlier. However, there was another wall, made of mud brick, which was associated with Jericho City IV. This wall would be the one encountered by Joshua.

Garstang also was not aware of the importance of the type of painted pottery which imitated Cypriot bichrome ware that he found in association with the destruction of City IV. "At the time of Garstang's excavation, the significance of this type of pottery was not recognized, so it was simply published along with all the other decorated pottery without being singled out for special notice." (Wood, 1990). This pottery has since been recognized as an indicator for the Late Bronze Age, i.e. the time from 1550 BC to 1400 BC. This pottery therefore supported Garstang's date for Jericho City IV, even though he did not recognize its importance in his publications. The presence of this pottery cannot be explained by Kenyon's Middle Bronze date. Although Garstang may be excused for not emphasizing the significance of the imitation Cypriot bichrome ware, it is puzzling why Kenyon ignored the report of such in Garstang's writings. Garstang's finding of this pottery needed to be explained if Kenyon's dating was to be credible, yet Kenyon never mentioned it.

Jericho: Kathleen Kenyon
In the 1950s, Kathleen Kenyon carried out explorations at Jericho. She redated the burning of Jericho City IV to 1550 BC, a century and a half before Garstang's date and well before any reasonable date for Joshua's conquest that could be derived from the Biblical text. She agreed with Garstang that the city was largely unoccupied for some decades after the conflagration, but whereas for Garstang's chronology this was a verification of the Biblical account, for Kenyon the conclusion was just the opposite. Kenyon's findings became widely accepted, and now it is common for skeptics to argue that since there was no city for Joshua to conquer in the late 15th century BC, the Bible's story of Joshua capturing Jericho is a fiction.

Kenyon dated City IV to 1550 BC, not on the presence of certain types of pottery, but on the absence of imported Cypriot pottery and other forms typical of the Late Bronze I period in her own excavations. "Although [Kenyon] also mentions certain local pottery types used in this period, it is obvious she paid little attention to these common domestic forms since they appear regularly in the final phases of City IV. That she did not focus more on the local pottery is especially strange because considerable stratified local daily-use pottery from the Late Bronze I period had been excavated and was available for her to work with even at the beginning of her excavation at Jericho. Instead, Kenyon chose to emphasize the imported wares in reaching her chronological conclusions" (Wood, 1990).

Critique of Kenyon's research
"Kenyon died in 1978 without living to see the final publication of her excavation of the tell. Her conclusions were reported only in a popular book published the year before she completed her fieldwork, in a series of preliminary reports and in scattered articles. The detailed evidence, however, was never supplied. This became available only in 1982 and 1983 when two volumes on pottery excavated from the tell were published.' (Wood, 1990)"

The final publication of Kenyon's work revealed that there were serious oversights or flaws in Kenyon's methodology. She ignored the common pottery types that were found in Jericho City IV, instead focusing on the imported Cypriot ware that she said was not present in in her area of excavation. The second problem, already mentioned, is that she ignored Garstang's report of finding extensive painted pottery and other local forms indicative of the Late Bronze Age in his excavations of City IV. Bryant Wood has offered two explanations why Kenyon found no painted pottery, whereas Garstang did. (1) The area excavated by Kenyon in City IV was confined to two 26 by 26 foot squares, which was one-thirteenth the City IV area excavated by Garstang. (2) The area was a very poor area of the city (Kenyon wrote "The picture given . . . is that of of simple villagers. There is no suggestion at all of luxury . . ."), and in a poor area one would not expect to find expensive painted pottery. Bryant Wood noted that Kenyon should have focused on what she did find in the way of pottery&mdash;the simple, locally produced ware that is associated with the Late Bronze Age, but which Kenyon did not make use of in drawing her chronological conclusions. Instead, she focused on what she did not find. Even with this, there is no satisfactory explanation of why she ignored Garstang's reports of painted pottery. Although Kenyon did an excellent job in introducing meticulous record keeping of the progress of archaeological excavations, yet her method of interpreting (or ignoring) what she and other archaeologists had found, and the conclusions she arrived at from such selective examination of the evidence, have shown the necessity of a fresh re-examination of the raw data of Jericho City IV uncovered by both her and Garstang.

Curiously, the conclusions that Kenyon drew in other areas have been abandoned by later scholars. But there is a certain tenacity with which her dating of Jericho City IV is maintained to the present day, contrary to the evidence that her handling of the Jericho data was selective and often unscientific. A part of this evidence has been presented in the present article. For additional information, see Wood 1990.

Jericho: Bryant Wood
During his studies for a doctorate in archaeology, Bryant Wood had occasion to read Garstang's various field reports, and, after 1982, the posthumous summation of Kenyon's work at Jericho. Since his main interest was pottery, Wood noticed the evidence for Late Bronze I pottery in Garstang's reports and the puzzling neglect by Kenyon in discussing what Garstang had found of this type pottery. Associated with this was Kenyon's unsound practice of dating of the small area of City IV that she excavated by what she had not found, rather than by what she had found, i.e. the ordinary domestic pottery that both she and Garstang discovered in abundance. But there were other considerations besides the pottery question that needed explanation. In the matter of stratigraphy, Wood points out the following:

"Kenyon was able to identify many different occupational phases during the Bronze Age at Jericho. Middle Bronze III, the last subperiod of Middle Bronze, lasted from about 1650 to 1550 B.C.E. The beginning of the Middle Bronze III phase at Jericho can be fixed quite confidently at Kenyon's Phase 32. From Phase 32 to the end of the life of City IV, Kenyon identified 20 different architectural phases, with evidence that some of these phases lasted for long periods of time. Over the course of the 20 phases there were three major and 12 minor destructions. A fortification tower was rebuilt four times and repaired once, followed by habitation units that were rebuilt seven times. If Kenyon were correct that City IV met its final destruction at the end of the Middle Bronze Period (c. 1550 B.C.E.), then all these 20 phases would have to be squeezed into a mere 100 years of the Middle Bronze III period. (Wood 1990)"

Wood further noticed that Kenyon's research did not properly account for the evidence of the Egyptian scarabs uncovered by Garstang. Scarabs are beetle-shaped amulets which frequently were inscribed with the name of the reigning pharaoh. These scarabs showed that the cemetery outside the city was in continuous use from the 18th century BC down to the early 14th century, i.e. the time of Eglon, king of Moab. Eglon had taken possession of the ruined city of Jericho a few decades after Joshua's death, building there a small palace (Judges 3:13). Egyptian scarabs, particularly those from the early 18th Dynasty, are evidence against Kenyon's claim that Jericho was not inhabited in the 15th century BC.

Correspondence of archaeological findings with the Biblical account
Several Biblical scholars besides Wood have noticed various phenomena associated with Garstang's and Kenyon's excavations in Jericho City IV that have a clear explanation in the Bible's story of Joshua's conquest:


 * The conquest happened in the early spring, just after harvest, since grain storage jars were full (Joshua 2:6, 3:15, 4:9, and 5:10 show that early spring was the time of Joshua's siege).
 * Because the storage jars were full, there could not have been a long siege before the city fell.
 * There were dwellings built up right against the outer (mudbrick) city wall, such as was the case for Rahab's dwelling.
 * The city wall collapsed to the base of the tell (Josh 6:20).
 * As established by Kenyon, it was after the walls fell that the city was burned with an intense conflagration.
 * Following the destruction by fire, the main part of the city remained uninhabited for a number of decades.
 * During the time when the city was basically uninhabited, there was found nevertheless an isolated palace-like structure that Garstang called the "Middle Building," dated to the 14th century BC. The resident here was well-to-do, as evidenced by a large quantity of imported Cypriot pottery.
 * The Middle Building was only inhabited for a short time. It's description and chronology fit the story of Eglon, king of Moab, who set up operations in the abandoned city of Jericho some decades after the death of Joshua, as recorded in Judges 3:12-30.

Critique of Wood's research
Wood's landmark 1990 BAR article called for a new evaluation of the date for Jericho's City IV based on the four considerations: pottery, stratigraphy, scarab evidence from the tombs, and the radiocarbon dating from a sample excavated by Kenyon. The first three considerations continue to be viable and have never been adequately refuted. But Wood's fourth argument, the radiometric, is now rejected. Wood correctly reported that the British Museum dated the wood sample from Jericho City IV at 1410 BC. However, it was later found that the calibration system and instrumentation of the British Museum's radiocarbon apparatus were giving wrong answers. This, of course, was no reflection on Wood's scholarship; he was reporting the results that everyone assumed to be correct when he wrote the BAR article. These radiocarbon results were superseded by a later study that examined various pieces of wood from Jericho and, more importantly, samples taken from the grain supply. The results of this later analysis now provide the main reason that the majority of scholars reject the Garstang/Wood date for Jericho City IV, even though this contradicts the other three types of evidence. Is there any explanation for this seeming contradiction between the date derived from archaeological evidence and that given by radiocarbon (C14) analysis?

Carbon-14 dating of the end of Jericho City IV
In 1995, Bruins and van der Plicht published a report on the radiocarbon measurements of some wood samples and also on grain samples taken from Jericho City IV (Bruins and van der Plicht, 1995). As expected, the wood (charcoal) samples gave an average age a few decades earlier than the grain samples, and so the six grain samples have been used as the primary indicator of when the city met its fiery destruction. These six samples produced a result of 3306 years BP (Before Present) with an impressive standard deviation of plus or minus only 7 years. The very small standard deviation reflects favorably on the careful sample preparation of the investigators and the accuracy of their mass spectrometer. There is no reason to question this initial result, and if that were all there were to it, it might be thought that the date of Jericho's destruction could now be ascertained, with a high degree of certainty, to within a 14 year interval.

Strange results from the adjusted C14 dates
Anyone familiar with radiocarbon techniques, however, knows that such is not the case. The problem is that a simple comparison of C12 to C14 ratios, such as gives the "BP" value, would not give the true age of a sample unless several conditions were satisfied. One of those conditions is that the rate of C14 production by cosmic rays in the upper atmosphere has been constant over time, an assumption that is generally recognized as invalid. Therefore over the years various checks have been applied to the basic BP values to see if there was a need for adjustment to the BP readings. The principal adjustment method is to compare BP values to the values given by tree-ring analysis, i.e. dendrochronology. The refinement of these adjustments is an ongoing study, and the results are published as calibration curves that transform BP values into historic BC or AD years.

Bruins and van der Plicht mention four calibration curves that they could choose from. The calibration system they settled on gave the following result: the 3306 BP figure (plus or minus 7 years) produces two date ranges for the samples: 1601-1566 BC or 1561-1524 BC. These date ranges (the ranges express the 1-sigma variation in each range) have median values 41 years apart, compared to the 7 year standard deviation in the original BP value derived from mass spectrographic analysis.

The most curious thing about these results is not that the four different calibration systems give different results, although the reconciliation of the various C14 calibration curves is of course a matter of much interest in the scholarly literature. The intriguing question is: how did the careful mass spectroscopic analysis that produced a ratio of C14 to C12 for which there was only a plus or minus seven year deviation figure for a period of 36 centuries, nevertheless come up with not one but two adjusted BC dates? Would anyone trust a calculator or computer that, given one very precise input, produces two answers for us to choose from?

This strange result (two answers to choose from) is because all calibration curves considered for use in this study showed a wiggle in the curve at just the time of interest, namely the middle of the second millennium BC. The wiggle (the curve essentially going back on itself) means that if you put in one BP date you will get out two BC dates. Physically, of course, this is not reasonable.The grain was all harvested in the same year, or at the most in two successive years. Yet this strange phenomenon is familiar to physicists doing C14 studies in the time range of the 16th and 15th centuries BC. For the unbiased observer, however, it should be clear that there are some genuine questions that can be raised about the reliability of the radiocarbon dates of the Jericho grain samples. Prudence would dictate that until the anomalous phenomena of C14 dating for this time can be explained, it would be better to rely on historical indicators for dating events in the middle of the second millennium BC rather than on radiocarbon results.

An adjustment to C14 dates suggested by the Thera data
The anomalous C14 results are not confined to Jericho. The Thera volcanic eruption article cites archaeologists who insist that the date range given by radiocarbon analysis (small grains) for the eruption of Thera, namely 1660 to 1600 BC, must be reduced by from 120 to 180 years if there is to be any consistency with dates that the Egyptologists give for Egypt's New Kingdom. If the median adjustment of 150 years is applied to the Bruin/van der Plicht results, then the first of their two date ranges, 1601 to 1566 BC, would be reduced to the range 1451 to 1416 BC. The second date range, 1561 to 1524 BC, would be reduced to 1411 to 1374 BC. Here there is inexactitude not only because of the calibrated C14 results, but also because of the few decades (but not a century) of uncertainty (120 to 180 years decrease) in the amount of adjustment recommended by the Egyptologists (see the Thera article). Nevertheless, the Egyptologists would insist that their figures cannot be reconciled with the radiocarbon results unless those are adjusted down by 120 to 180 years. Even the minimum adjustments of 120 years combined with the maximum Bruin/van der Plicht date (1601) would rule out Kenyon's 1550 date for Jericho City IV.

These recent developments and ongoing controversy in the field of radiometric analysis were unknown when Wood published his 1990 BAR article calling for a reexamination of the archaeological data published by Garstang and Kenyon. If it is decided that the dust needs to settle in this dispute before the C14 evidence can be evaluated fairly, then the dates for Jericho City IV should be determined solely based on archaeological arguments. These, it has been maintained, definitely favor the Garstang/Wood dating. If, however, the revision in C14 dates in the mid-second millennium BC called for by the Egyptologists is right, then all conflict between radiocarbon measurements and archaeological evidence for the date of the fall of Jericho City IV would be resolved. That resolution would rule out the 1550 date that is currently in favor in most secular publications, and explain why it is in contradiction to the archaeological data. If such a resolution to the conflict were to come about, then Dr. Wood's 1990 reexamination of the Jericho data will surely be recognized as a major contribution to the understanding of the history of Egypt and the Levant in the second millennium BC.

With either solution, Kenyon's conclusions cannot be correct
There is an interesting consequence to this that results if either of the alternatives is chosen—that of the physicists or that of the Egyptologists. It has just been mentioned that the solution of the Egyptologists requires a down-dating of C14 results. This would establish that the adjusted radiocarbon dates for Jericho City IV are in accordance with the Garstang/Wood chronology and in contradiction to Kenyon's chronology. Those who advocate the Biblical trustworthiness will definitely prefer this alternative. But the other option, namely that Egyptian dates for the 18th Dynasty must be updated about 160 years to conform to C14 results, would also be fatal to Kenyon's interpretation of the archaeological data.

The reason is that her date of ca. 1550 BC for the destruction of City IV would necessarily be adjusted to about 1710 BC. According to Kenyon's writing (also verified by Garstang, Wood, and other archaeologists), this destruction was followed by about 350 years in which the city was basically uninhabited. This is the chief argument that has been used for over 50 years now against the historicity of the Biblical account of Jericho. But although the 160-year adjustment can be made to the stratigraphic and pottery findings, it cannot be made to the C14 results under the assumption that the physicists are right. The grain found in Jericho's storage jars would still be dated to about 1550 BC, which is in the time that the adjusted Kenyon dates would dictate that the city was uninhabited. This is fatal to Kenyon's entire dating scheme. Either solution—that of the Egyptologists or that of the physicists—cannot be supported by Kenyon's conclusion that Jericho fell at about the time of the beginning of the New Kingdom, whether that was in the middle of the 16th century BC (unadjusted date) or 160 years earlier (adjusted date). This is the consequence that seems inescapable once the dilemma posed by the current controversy over C14 dating in the middle of the 2nd millennium BC is fully grasped. Kenyon's conclusion that Jericho fell at about the time the 18th Dynasty began cannot be reconciled with either solution to the dilemma. Currently the only solution that seems to have any semblance of credibility is the Biblical solution: Jericho fell to the armies of Israel in the latter part of the 15th century BC, and the C14 evidence, properly interpreted and adjusted, now supports the Biblical account.

Related links

 * Carbon-14 dating
 * John Garstang
 * Bryant Wood
 * Thera volcanic eruption