Toto (died 29 July 768) was the self-styled duke of Nepi, the leading magnate of Etruria, who staged a coup d'état in Rome in 767. He became Duke of Rome for a year until his death. The principal sources documenting his takeover are the vita of Pope Stephen III in the Liber Pontificalis and a surviving deposition of the primicerius Christopher from 769, preserved in a ninth-century manuscript of Verona, the Depositio Christophori.
Toto's origins are obscure. His name is Germanic, probably Lombard, but Nepi lay within the Duchy of Rome on the frontier with the Duchy of Tuscia. The Liber Pontificalis calls him "Toto quidam dux, Nepesinae civitatis dudum habitator", a certain duke long resident at Nepi. The Depositio Christophori refers to him as "quidam Nempesini oppidi ortus, Toto nomine", a man born in the fortress of Nepi, Toto by name.Thomas Hodgkin refers to him as a "citizen of doubtful nationality ... who had by means unknown to us acquired the dignity of a dukedom", meaning a Roman citizen, but a native and resident of Nepi, who employed the title dux, but with or without legal justification is uncertain.
In 767 Pope Paul I fell ill. Toto, with his brothers Constantine, Passivus (Passibo) and Paschal, gathered a large army from Nepi, the other Etrurian towns, and the rustici or contadini (peasant conscripts), and entered Rome by the gate of Saint Pancras (San Pancrazio). He then settled down in his townhouse to wait things out, intending probably to influence the election of a papal successor. The primicerius Christopher drew an oath from Toto that he would not interfere in the coming election, but when Paul died on 28 June, he seized the Lateran Palace and declared his lay brother Constantine pope. The following day, George of Palestrina, the vicedominus, who was in the palace at the time of the coup, was forced to ordain Constantine a subdeacon and deacon in the chapel of Saint Lawrence. The population of Rome was ordered to swear allegiance to Constantine and, six days later, he was consecrated bishop by George, Eustratius of Albano, and Citonatus of Porto.