Ancient documents tell us the rich story of Montalto and its origins which date back to 762 BC in the height of the Longobardo dominion. A bishop from Lucca consecrated a chapel that was dedicated to Saint George, commisioned by Causari, son of Achis who was also consecrated on the 2nd of October of 762. As a dowry, Causari donated all the cultivated land, vineyards, fields and woodlands surrounding the area to the small church.
It also tells that from 1130 it began to form into a castle, located on the canal that today divides Montopoli and San Miniato.
Being a border zone made it a constant strategic position for revenge and was often the object of bitter feuds and claims between the Ghibellini's of Pisa and the Guelfi's of Florence.
In 1335, after the seemingly endless struggles, the Castle was abandoned and only few testimonials and reports remained. Today one can still visit the grounds by walking in the woods nearby, passing through the foundation of the Chiesetta di San Silvestro, which is still vigiliantly cared for.