Here's why:
* Metonymy is a figure of speech where a word or phrase is substituted for another with which it is closely associated.
* In this case, "deeds" are being used to represent the kings themselves. The phrase is not literally referring to the physical acts of the kings, but rather their legacy, impact, or achievements, which are all connected to the concept of the kings themselves.
Therefore, "deeds of dead kings" is a concise and evocative way to evoke the entire concept of the historical figures and their impact on the world.