The years from 511 to 507 had been tumultuous for Athenians. Cleisthenes had redirected their government in the direction of a strongly direct democracy, they had repulsed by force the attempt to seize control of their state by Cleomenes of Sparta and his Athenian collaborator Isagoras, and they had made the fateful decision to ask the Persian king for a protective alliance. As the next decades would reveal, the events of these few years deeply affected the social and political conditions of the Athens into which Pericles was to be born in the mid-490s. They also taught harsh lessons pertinent to his own career that Pericles would learn from his parents' stories about the history of Athens when they themselves were young. Those maxims were easy to summarize but disturbing to contemplate. For one, trusting the Spartans was disastrous; they might claim to support liberation, but they could do an abrupt about-face and promote tyranny when it suited them. For another, the Greeks bordering on Athenian territory (the region called Attica) were also untrustworthy; the Athenians lived in a very treacherous neighborhood with much to fear. Home was also politically hazardous; some Athenians were willing to subvert democracy and resort to tyranny or oligarchy to promote their own advantage. Finally, Pericles could always expect his opponents to try to make trouble for him by exploiting his Alcmeonid lineage and the curse attached to his mother's family. The history of the years and decades to follow would confirm and expand these warnings for Pericles as he grew up.

Pericles' mother, Agariste, married his father, Xanthippus, around 500 or a few years later. Her first child was a son, Ariphron, named after her husband's father, as was customary. She also had a daughter, but neither the baby girl's birth order nor her name is preserved in the ancient sources. Agariste was probably in her late teens at the time of the marriage, Xanthippus in his mid- to late twenties. This difference in age was customary at Athens for brides and grooms in the upper class. When Xanthippus married into the Alcmeonid family, he was stepping up the social ladder. His name, meaning something like “Blond Horse,” was a kind of “horsey” name with an upper-class sound that richer Greeks liked to give their children.