Demaratus of Corinth
Demaratus, frequently called Demaratus of Corinth, was the father of Lucius Tarquinius Priscus, the fifth King of Rome, and the grandfather or great-grandfather of Lucius Tarquinius Superbus, the seventh and last Roman king.
Demaratus was a nobleman of the Dorian House of the Bacchiadae at Corinth. Facing charges of sedition, in 655 BC he fled to Italy, according to tradition settling in the Etruscan city of Tarquinii, where he married an Etruscan noblewoman. They had two sons, Lucius and Arruns.
According to tradition, Demaratus introduced Greek culture to mainland Italy, and brought potters from Corinth; Greek potters worked at Tarquinii and its port, Gravisca. Tacitus reported that Demaratus brought literacy to the Etruscans. According to Pausanias, Demaratus' son or grandson was the first foreigner to visit Olympia, and make a dedication there.
Through his sons, Demaratus was the ancestor of the Roman gens Tarquinia. Arruns Tarquinius died shortly before his father, leaving his wife pregnant. As Demaratus knew nothing of his future grandson, he left him no inheritance. For this reason the child, likewise named Arruns, was born into poverty, and called Egerius, meaning "the needy one."
As the son of a foreigner, Lucius Tarquinius was unable to attain high station at Tarquinii, despite his wealth and the nobility of both his mother and his wife, Tanaquil. With Tanaquil's encouragement, he migrated to Rome, where he won the favour of the king, Ancus Marcius. When Marcius died, Tarquin succeeded him to the throne. After subduing the Latin town of Collatia, the king placed his nephew in charge of the Roman garrison there.
Lucius Tarquinius was the father or grandfather of Lucius Tarquinius Superbus, the seventh and last King of Rome. He was also the father-in-law of Servius Tullius, the sixth King of Rome, who reigned between the two Tarquins. An Etruscan tradition reported that Servius, aided by the heroes Aulus and Caelius Vibenna, defeated and killed a group of enemies, including a certain Gnaeus Tarquinius of Rome, perhaps the son of Tarquin the elder and father of Tarquin the Proud. In this case, the elder Tarquin was the grandfather of Lucius and Arruns Tarquinius, and the former's sons, Titus, Arruns, and Sextus.
Lucius Tarquinius Collatinus, one of the first Roman consuls in 509 BC, was the son of Egerius. At the urging of his colleague, Lucius Junius Brutus, he chose voluntary exile from Rome in order to assuage hostility of the people towards the former ruling house, in spite of his unblemished reputation, and the fact that the revolution itself was instigated by the rape of Collatinus' wife, Lucretia, at the hands of Sextus Tarquinius. Ironically, Brutus, who held the consulship until his death in battle later that year, was more closely related to the royal household than Collatinus; his mother was the king's sister. But it was the name of Tarquinius that was so reviled that it brought about Collatinus' resignation and exile.
According to various traditions, Demaratus' descendants would have included not only the gens Tarquinia, but also the Junii and the Mamilii; Octavius Mamilius, the dictator of Tusculum, was a son-in-law of Tarquin the proud, and some of his descendents came to Rome during the fifth century BC. Some of the Tullii also claimed descent from Demaratus through Tarquinia, the wife of Servius Tullius, although no tradition mentions their sons.
A Blakeway, "Demaratos" Journal of Hellenic Studies 1939, pp. 129ff.