The most important of them are the following: (1) The daughter of Cypselus, king of Arcadia, and wife of Cresphontes, ruler of Messenia.
During an insurrection Cresphontes and two of his sons were murdered and the throne seized by Polyphontes, who forced Merope to marry him.
The fortunes of Merope have furnished the subject of tragedies by Euripides (Cresphontes, not extant), Voltaire, Maffei and Matthew Arnold.
The last of these attempts resulted in the " Dorian conquest " of the "Achaeans " and " Ionians " of Peloponnese, and in the assignment of Argolis, Laconia and Messenia to the Heracleid leaders, Temenus, Aristodemus and Cresphontes respectively; of Elis to their Aetolian allies; and of the north coast to the remnants of the conquered Achaeans.
In Messenia (according to a legend dramatized by Euripides in the 5th century, and renovated for political ends in the 4th century) the descendants of Cresphontes quarrelled among themselves and were exterminated by the natives.
A body of Dorians under Cresphontes invaded the country from Arcadia, and, taking as their capital Stenyclarus in the northern plain, extended first their suzerainty and then their rule over the whole district.
At last, Temenus, Cresphontes and Aristodemus, the sons of Aristomachus, complained to the oracle that its instructions had proved fatal to those who had followed them.