Here's why:
* Metonymy is a figure of speech where a word or phrase is substituted for another that is closely associated with it.
* In this case, "deeds of dead kings" represents the entire legacy and history of those kings. The deeds themselves stand in for the kings' lives, their rule, and the impact they had on their kingdoms.
The phrase is powerful because it evokes a sense of both grandeur and mortality. It reminds us that even the most powerful figures are eventually overcome by death, leaving behind only their actions for posterity.