The Ptolemaic Dynasty ruled Egypt and much of the eastern Mediterranean basin for nearly 300 years.
As a Macedonian dynasty, they derived much of their legitimacy from military activity.
As an Egyptian dynasty, they derived much of their real wealth and power from maintaining a secure hold on their new homeland.
As lords of a far-flung empire, they maintained much of their authority through garrisons and the threat of military action.
To achieve this they devoted much of their activity to the de.