After his removal from power, Demaratus sought refuge in the Achaemenid Empire, where he was welcomed by King Darius I.
He was granted land and cities in Asia Minor, integrating him into Persian society while retaining his influence.
Demaratus served as an advisor to Xerxes I during the Second Persian invasion of Greece, providing strategic insights about Greek military tactics.
His father's significance in the highly structured Spartan society meant Demaratus' firstborn status held considerable weight.
According to Herodotus, Demaratus' birth was accompanied by a prophecy that suggested his future prominence and influence, with his name meaning "wished by the people.
Athens at once appealed to Sparta to punish that act of medism, and Cleomenes I crossed over to the island to arrest those responsible.
In retaliation, Cleomenes urged Leotychidas, a relative and personal enemy of Demaratus, to claim the throne on the grounds that the latter was really the son not of Ariston but of Agetus, his mother's first husband.
Leotychidas' anger towards Demaratus was due to a dispute over the marriage of Perkalon, the daughter of Chilon, son of Demarmenos.
There has never been a time when poverty was not a factor in the rearing of the Greeks, but their courage has been acquired as a result of intelligence and the force of law.
Afterward, however, his sons, Eurysthenes and Prokles, succeeded him in ruling over the cities of Halisarna and Teuthrania in Aeolis.
[6] In general, they were generously rewarded by the Achaemenid kings, received land grants to support them and ruled over various cities in Asia Minor.