In a study conducted by researchers from four prestigious Israeli universities, the ancient Philistine city of Gath's conquest by Hazael King of Aram has been scientifically verified. This remarkable achievement relies on a new technology that interprets archaeological findings from Biblical times by measuring the magnetic field recorded in burnt bricks.
The multidisciplinary study, led by Dr. Yoav Vaknin from Tel Aviv University and the Palaeomagnetic Laboratory at The Hebrew University, along with contributions from esteemed scholars, has significant implications for understanding the intensity of fire and the extent of destruction in Gath. Furthermore, it sheds light on the construction practices prevalent in the region during that era.
The researchers' innovative method enables the identification of burnt materials discovered in excavations and estimation of their firing temperatures. By applying this technique to ancient Gath, also known as Tell es-Safi in central Israel, they were able to validate the Biblical account found in the Second Book of Kings, which states, "About this time Hazael King of Aram went up and attacked Gath and captured it. Then he turned to attack Jerusalem" (2 Kings 12, 18). Unlike previous methods, this new approach can determine whether specific items, such as mud bricks, underwent firing events even at relatively low temperatures, starting from 200°C and above. This breakthrough information is crucial for accurate interpretation of archaeological findings.
The key to this method lies in measuring the magnetic field "locked" within the bricks as they burned and cooled down. The clay used to make these bricks contains millions of ferromagnetic particles that behave like tiny compasses or magnets. In sun-dried mud bricks, the orientation of these particles is random, resulting in a weak and non-uniform magnetic signal. However, when these bricks are subjected to high temperatures, such as those in a fire, the magnetic particles align themselves with the earth's magnetic field at that specific time and place. As the bricks cool down, the magnetic signals remain locked in their new position, creating a strong and uniformly oriented magnetic field that can be measured using a magnetometer. This indicates that the brick has indeed been fired.
To validate their method, the researchers conducted controlled experiments in the laboratory. They fired mud bricks under specific temperature and magnetic field conditions, measured the magnetic field acquired by each brick, and gradually erased it through thermal demagnetization. This process involves heating the brick in a specialized oven that neutralizes the earth's magnetic field, causing the magnetic signals to arrange randomly once again, resulting in a weak and unoriented magnetic signal.
The team's method proved highly sensitive, capable of detecting changes in the magnetic signal at temperatures as low as 100°C. This sets it apart from other techniques that rely on changes in minerals occurring at temperatures higher than 500°C. Additionally, the researchers used infrared radiation absorption to verify the results of their magnetic method, further enhancing the credibility of their findings.
The researchers applied their method to settle a long-standing archaeological dispute regarding a specific brick structure discovered at Tell es-Safi, believed to be the ancient Philistine city of Gath. The prevailing hypothesis, supported by the Old Testament, historical sources, and carbon-14 dating, suggests that the structure's destruction resulted from the devastation of Gath by Hazael, King of Aram Damascus, around 830 BCE. However, a previous study proposed that the building had not burned down but rather collapsed over time, and that the fired bricks found in the structure were fired in a kiln before construction. This would have implied the earliest instance of brick-firing technology in the Land of Israel.
Using their innovative method, the researchers examined samples from the wall at Tell es-Safi and the collapsed debris alongside it. The results were unequivocal, with the magnetic fields of all the bricks and debris displaying the same orientation: north and downward. This signifies that the bricks burned and cooled down in the structure itself during a conflagration that caused its collapse within a few hours. Had the bricks been fired in a kiln and then laid in the wall, their magnetic orientations would have been random. Moreover, if the building had collapsed gradually over time, the debris would have exhibited random magnetic orientations. The previous interpretation failed to identify burning at temperatures below 500°C, leading to a flawed conclusion. The researchers' method, however, revealed that all the bricks in the wall and debris had burned during the conflagration, with those at the bottom experiencing relatively low temperatures below 400°C and those in upper layers or fallen from the top reaching temperatures higher than 600°C.
These findings hold immense historical and archaeological significance, shedding light on the intensity of the fire and the extent of destruction in Gath, which was the largest and most powerful city in the Land of Israel at the time. Additionally, they provide invaluable insights into the building methods employed during that era. Furthermore, the study highlights the ecological implications of ancient building techniques, as brick firing requires vast amounts of combustible materials, potentially leading to deforestation and the loss of certain tree species in the area. The researchers speculate that brick firing was likely not practiced in the Land of Israel during the times of the Kings of Judah and Israel.
