Following Priscus’s death, his son-in-law Servius Tullius succeeded him to the throne, the second king of Etruscan birth to rule Rome. Like his father-in-law before him, Servius fought successful wars against the Etruscans. He used the treasure from the campaigns to build the first walls to fully encompass the Seven Hills of Rome, the pomerium. He also brought about reforms within the Roman army.

He was renowned for implementing a new constitution for the Romans, further developing the citizen classes. He instituted the world’s first census which divided the people of Rome into five economic classes, and formed the Century Assembly. He also used his census to divide the people within Rome into four urban tribes based upon location within the city, establishing the Tribal Assembly. His reign is also given credit for building the temple to Diana on the Aventine Hill.

Servius’ reforms brought about a major change in Roman life: voting rights were now based upon economic wealth, transferring much of the power into the hands of the Roman elite. However, as time passed, Servius increasingly favored the most impoverished people in order to obtain favors from the plebs. His legislation was very distasteful to the patrician order. Tullius’s reign of 44 years was brought to an end after his assassination in a conspiracy led by his own daughter Tullia and her husband Tarquinius Superbus.