In the itinerary of Archbishop of Canterbury Sigeric the Serious, the city of Porcari represented the 25th stage, and was called by the name of Forcri. The first document regarding Porcari is dated April 30, 780, when 3 Lombard nobles : Gumberto, Ildiberto and Gumbardo Calci left to settle in “Porchari”.
The town was located on the shores of Lake of Sesto and by the Via Roma, thus becoming an important communication route to Florence, Pisa and Lucca. The lake of Sesto, now dried up, was an important source of livelihood for the first human settlements in the region. Some archaeological excavations have been carried out and discovered signs of successive occupation dating back to the Upper Paleolithic in nearby Fossa Nera, Fornace and Casale Nardi sites.
Situated in Porcari, on the left bank of the Serchio (in antiquity the Auser), the archaeological site of Fossa Nera shows periods of abandonment and of successive occupation, closely related to the particular environmental conditions along the Serchio, which tended to flood the area. Fossa Nera preserves substantial remains of Roman rural dwellings. The archaeological explorations conducted since 1987 have also identified layers of a Bronze settlement village and a 5th century B.C. Etruscan settlement. More recently, a second Roman settlement from the 2nd century B.C. has also been discovered on the opposite bank of the river.