Originally named Lucumo, he was a very wealthy man from the Etruscan town of Tarquinii. His mother was and Etruscan, but his father, Demaratus, was a very wealthy fugitive from the Greek city of Corinth. When his father died, he left all of his state to Lucumo, because his other son Arruns had died recently. What Demaratus had not known was that Arruns' wife was pregnant. When she gave birth, she named the child 'Egerius,' for he would be 'Needy.'
Lucumo, on the other hand, was left with fabulous wealth. He married Tanaquil, the daughter of a noble Etruscan family. Being a noble, she expected her husband to pursue a course of political advancement and power. Lucumo, however, was not of pure Etruscan birth, since his father was from Corinth. He therefore was considered a foreigner by the people of Tarquinii. Tanaquil could not tolerate having a husband, whom no one would give respect. She convinced her husband to leave their home and move to Rome, a new city where his wealth could afford him prestige.
Once in Rome, he adopted the name of Lucius Tarquinius Priscus. He quickly made many friends, among whom was the aging Ancus. He became the king's closest advisor. Upon Ancus' death, Tarquin quickly made his move for the throne. He arranged for Ancus' sons to be away on a hunting expedition, and then began to openly campaign for the throne, something which no previous king had done. A vote was held and the people elected Tarquin.
Tarquin's first action as king was to double the number of senators to 200. By doing so the newly appointed-senators would naturally support Tarquin, giving him a firm power base in the senate.
Tarquin also set about improving Rome, which was still rather rustic. He created the Circus Maximus, for the entertainment of the people. The Circus consisted of a track one mile in circumference, with temporary bleachers erected around it when an event was to be held.
Tarquin also improved the military of Rome. During his reign, he fought against the nearby Latins and Sabines. To better fight against these people, he decided to increase double strength of the cavalry. That more men were able to afford horses is also a sign that Rome was becoming more prosperous. Unlike the previous kings, Tarquin's victories were far more reaching. Under the Etruscan influence, Rome was on its way towards becoming a regional power.
During his reign, an unusual event took place at the palace. While a little slave boy named Servius Tullius was sleeping, his head caught on fire. Everyone watched the flames. Amazingly, the little boy continued to sleep. Another slave fetched water and was about to put them out, when Tanaquil commanded him to stop. After a few minutes, the child woke up and the flames went out. Tanaquil told her husband that the flames were a sign that this slave boy was special. From then on, Servius Tullius was raised by Tarquin as if he were his own son. Tarquin eventually married his daughter to him.
In the 38th year of Tarquin's reign, there was an attempt upon his life. The two sons of Ancus Marcius, still upset about the deceitful manner in which Tarquin had become king, decided to take action. It had become clear to them that after the death of Tarquin, Servius Tullius would become king, instead of one of them.
The sons hired two shepherds, men who would naturally carry weapons with them, to assassinate the king. The two began a brawl at the entrance to the palace. They yelled that the king should settle this matter for them. The king and his lictors separated the two men. Then, when Tarquin stepped between the two and turned to talk to one, the other split his skull with an axe. Then the two shepherds fled for the door.
Seeing Tarquin would soon die, Tanaquil immediately assumed control over the situation. She ordered the doors of the palace closed. She ordered her slaves to prepare medicines, and went up to the balcony and announced to the people that the king would be fine, having only been stunned by the blow.
To Servius Tullius she told the truth, and said he must now claim his throne. He went out among the people wearing the purple robe and accompanied by the lictors. He claimed merely to be acting as king until Tarquin was better. Hearing that the king was still alive, the sons of Ancus Marcius fled from Rome into exile.
Livy. Ab Urbe Condita.