The gigantic eruption of Thera (now called Santorini) was one of human history’s most explosive volcanic events and perhaps the greatest in the last four millennia. The date of its occurrence, 1650 BCE, is a chronological pivotal point in the second millennium BCE Middle Eastern history. That event and its widespread effects on climate conditions influenced events in Minoa, Greece, Egypt, the Levant, Babylonia, west-central Asia, India, and China.
For example, it caused a massive famine in China; in Western Asia, temperatures dropped severely, and very little precipitation occurred. The sheepherders living near the Ural Mountains had to journey south to a wetter and warmer climate in southern Asia, particularly in India and Mesopotamia. This was the third and largest of the immense Indo-Aryan migrations. (Very wet conditions instigated the first of these migrations around 1750 BCE, then excessively arid conditions caused the second around 1700. For more details about these events and their timing, see the forthcoming The Six Pillars Chapters 4 and 8.) Their descendants, collectively called the Kassites, became the rulers of Babylonia after the end of Hammurabi’s Amorite Dynasty in 1595 BCE.
The well-known Venus Tablet of Ammi-şaduqa was originally a record that compiled the observations of the rising and setting of Venus over 21 years. That Babylonian Amorite king began his rule in late 1647 or early 1646, just three years after the Thera eruption. The Venus Tablet was a unique document because no evidence from that kingdom exists of a similar regular collection of astronomical records of one planet until many centuries later. Why did they suddenly have such an intense interest in these regular observations? It was probably because they associated the planet Venus with Inanna, a fertility goddess, and one effect of the eruption was to disrupt farming. The hazy atmosphere after the eruption caused the observations of the planet’s rising to be much later than usual and its setting to be early. Thus, those records were a practical measure of gradually improving visibility and the return of warmer and wetter conditions—improvement in atmospheric clarity correlated with the consequent increases in farm yields.
All these points are important historical details. Nevertheless, the date of the eruption is perhaps the most significant in the chronology of Egypt because it signifies the end of the Egyptian Hyksos Fifteenth Dynasty. Some more minor volcanic activity occurred on Thera before the massive Plinian event, which coincidentally happened during the annual flooding of the Nile River when it was near its peak inundation. (See the drawing of flood levels by month.) Three factors contributed to the deadly flood levels that Ahmose I recorded in his Tempest Stela: the peak annual flood, tsunamis, and volcanic rain. That enormous volume of water swept away the Hyksos capital city, Avaris, and its fortress.
The Upper Egyptian (southern) Seventeenth Dynasty under King Ahmose I was already at war with the Hyksos. After the flood subsided, the southern forces resumed their attack. With the Hyksos capital city gone, it did not take long for the Fifteenth Dynasty fighters to retreat to the Levantine city of Sharuhen. When Ahmose I began to rule over Lower Egypt (the north), northern officials considered his rule a separate dynasty. From their perspective, the Seventeenth Dynasty became the Eighteenth.
Thus, a critical aspect of this fixed date of 1650 BCE for the end of the Hyksos rule in Lower Egypt is that we can calculate earlier dates for the Fifteenth and Seventeenth Dynasties. Unfortunately, little king list information is available for the Seventeenth Dynasty. But, as we have seen, the Fifteenth Dynasty lasted at least two centuries. Although mistranscriptions have garbled Manetho’s figures, a reasonably reliable Fifteenth Dynasty king list is constructible from that data, and that dynasty likely ruled for about 220 years.
Synchronisms between the Fifteenth and other Egyptian Dynasties and other clues can help rebuild their timelines. Moreover, those Hyksos kings also have chronological links to Minoa, the Levant, and Mesopotamia.
The primary basis for the conventional dating of these dynasties is the mistaken dogma of a single calendar system. The most dependable way to synchronize the Fifteenth Dynasty with the other Second Intermediate Period and Twelfth Dynasty kings is through archaeological finds with artifacts from different dynasties in the same contexts, scarab styles, and art and architectural similarities.