On the comune's coat of arms there is a pig, and two explanations that do not agree. The first says the arms join two old seals: that of Serravalle, which was a grille, for a name understood as the closing of a valley, and that of Larciano — once Lerciano — which took the wild pig as a canting device, that animal being held to be filthy. The second is Luigi Passerini's, who in 1864, in the Arms of the Tuscan municipalities, maintained that it is not the comune's emblem at all but the coat of arms of Francesca Forteguerri, wife of messer Giovanni dei Cancellieri, painted inside the town hall — the golden pig of the Cancellieri joined to the vair of the Forteguerri — and mistaken for the town's own. The castle above the village was fortified by Pistoia in the twelfth century, the Rocca Nuova was built by the men of Lucca in 1302, and an inventory of about 1380 records it as the castrum Serravallis, with walls and towers all around and two gates.
Then there are two things the village remembers precisely. Tradition tells that at the beginning of the fourteenth century a pilgrim and a child asked for hospitality here and were taken in, and that the child was Louis of Anjou, son of the king of Naples and heir to the throne, who left the crown for the Church and became a saint: keeping the promise he made then, many years later he is said to have saved Serravalle from the siege the men of Lucca laid to it in 1306. And in the last war the comune was one of those designated in Tuscany for the civil internment of foreign Jews. Among the people staying here were the Cittone, father, mother and five children, who had come from Livorno as evacuees to escape the bombing. On the twelfth of January 1944 the whole family was arrested, on the denunciation of the local carabinieri marshal, and deported to Auschwitz: one of the largest groups deported from the province of Pistoia. Only Sol Cittone came back, then a girl of fifteen; seventy years later, on the fifteenth of October 2014, she returned to Serravalle for a ceremony the comune held in her honour.