Hippocrates cured many illnesses—and then fell ill and died. The Chaldaeans predicted the deaths of many others; in due course their own hour arrived.
(Meditations by Marcus Aurelius, translated by Gregory Hays.)
My misunderstanding is why the word deaths is used with the here. There is no context preceding this sentence in which we could find information about the Chaldaeans' predictions, so would the meaning change if the is left out?
In the other hand, there is no article before many illnesses. What's the difference between these two cases?