After the death of Tullus Hostilius, the people elected Ancus Marcius as their king. The senate then ratified their selection. Ancus was the grandson of Numa, the second king of Rome, and his selection indicates the people of Rome had grown tired of the endless wars under Hostilius.
Ancus immediately set about restoring the religious observances of his grandfather. To the war-weary Romans, this was a welcomed change. To the surrounding towns, this was a signal that Rome was now weak militarily. Led by the town of Latium, the surrounding Latin peoples sought to take advantage of the situation.
What the Latins soon found out, however, was that Ancus was religious like his grandfather Numa, but was just as capable in war as Tullus Hostilius. He left the appointed priests of Rome to deal with religious matters, while he himself led the soldiers against the Latins. Ancus razed several smaller towns and transferred their citizens to Rome, once again greatly increasing the population of Rome.
Perhaps the most important accomplishment of Ancus' reign was the building of Ostia, Rome's port on the Tyrrhenum Sea (the Mediterranean Sea west of Italy).
During his reign a man named Lucumo left from the Etruscan town of Tarquinii and arrived in Rome. Not of noble birth, the Etruscans had despised the wealthy Lucumo. Because of this, he decided to settle in 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.
After 24 years of ruling Rome Ancus Marcius passed away.
Livy. Ab Urbe Condita.