SPQR (Senatus Populusque Romanus)

The Roman Senate and People.
After defeating Tarquin, the last Roman king, the people started a new type of government; a Republic.
As a publicity and propaganda campaign, engraved into marble, wrought or emblazoned, the official identifier for drain covers and much more stands for the Senate and the People of Rome.
Today SPQR is still the municipal symbol of the city of Rome.