King Ancus Marcius

Rule by the book
Ancus Marcius was the fourth of the Roman kings. He had seen how Tullus Hostilius had neglected the duties to the gods as these were established by Numa Pompilius, who was his grandfather by his mother.  Ancus had all the rites of the religion recorded on white tables  by the pontifices and had these tables displayed at a public place.

Hope for peace
Both the neighboring cities and his own subjects now had hopes for peace like in his grandfathers time. But after a while the Latins thought he wouldn't make war and started to invade Roman territory and sent the complaining Roman ambassadors empty handed back.

The proper start of a war
Ancus Marcius, who liked to do the things by the book, now designed the proper rites to start a war.  A complete procedure  how there had to be asked for  restitution , given 33 days to comply and how the war should be declared by the fetiales in case of refusal.

Always a just war
After having done so, war was declared to the Latins; by the book. He conquered several Latin cities and enlarged the Roman territory to the sea at Ostia. Also he enlarged the city to harbor the new inhabitants from the cities he had destroyed.