The reason for the decline of the Hellenic-Egyptian civilization of the Ptolemies in Egypt was not the slave revolts, but the volcanic eruptions that destroyed the agriculture and the economy of the state. To this conclusion scientists came.
Francis Ludlow and other co-authors published an article in Nature Communications, in which, comparing the historical data from 622 to 1902 AD, e. with information on the volcanic eruptions of that time, reported that they led to whole periods of low spills.
Mass emissions of volcanic gases – primarily sulfur dioxide – reduce the amount of solar radiation, which can lead to a decrease in global temperature and precipitation, and also affects the behavior of the Nile.
Turning to the period 350-30 years. BC. e., the last time of the independence of Egypt and the rule of the Ptolemaic dynasty, which ended in complete defeat from Rome, they drew attention to the eruption of the Italian Etna in 44 BC. e.
Scientists supplemented these data with ancient written testimonies that documented the growth of taxes and social instability, popular riots and friction with neighbors, famine and epidemics. In some cases, all this followed immediately after the eruption, in others – with a delay of one year.
Thus, they came to the conclusion that it was the drop in yield caused by the activity of volcanoes that stimulated the death of the once great civilization.