[Left plaque]
15 LUGLIO 1920
BARZI ROBERTO / MARIANI GIUSEPPE
TABARR’NI GIULIA / OLIVI VIRGILIO
PICCIO VIRGILIO / CERBONI LORENZO
AI MARTIRI DI PANICALE
TRUCIDATI DALLA REAZIONE
I COMPAGNI SOCIALISTI E COMUNISTI
A PERENNE RICORDO POSERO

[Center plaque]
AGLI EROI
CHE CON IL SACRIFICIO DI LORO GIOVANI VITE L’ONORE, LA SORTE, LA GLORIA D’ITALIA
ASSICURARONO
LA POPOLAZIONE DEL COMUNE P. ANNO MCMXX
[names]

[Right plaque]
SIA GLORIA ETERNA AI GENEROSI
CHE S’IMMOLARONO PER LA LIBERTA D’ITALIA
SIA LA IMPERITURA RICONOSCENZA
DELLE NUOVE GENERAZIONI VERSO QUEI PRODI
FIAMMA PERENNE ALIMENTATRICE
DI CIVILI VIRTU’
18 SETTEMBRE 1910

The events of 1920 in Panicale: Peasant demonstrations culminated on July 15, 1920, when a protest march was violently suppressed by the Carabinieri (Italy’s military police force). 6 protesters were killed and 14 were injured.

The left panel is about this event.
It is possible that the central plaque, which also shows the year 1920, commemorates those who fell in the First World War
It is not known what came to commemorate the right panel (18/9/1919)

The place where the sign is located was photographed on the same day by the same photographer Click for a larger image

Below are the panels enlarged as they were taken that day by the same photographer:
The left panel Click for a larger image
The central panel Click for a larger image
The right panel Click for a larger image

Translation of the text on the sign:
[Left plaque]
15 JULY 1920
BARZI ROBERTO / MARIANI GIUSEPPE
TABARR’NI GIULIA / OLIVI VIRGILIO
PICCIO VIRGILIO / CERBONI LORENZO
TO THE MARTYRS OF PANICALE
MURDERED BY THE REACTION
THE SOCIALIST AND COMMUNIST COMRADES
IN EVERLASTING MEMORY THEY PLACED

[Center plaque]
TO THE HEROES
WHO WITH THE SACRIFICE OF THEIR YOUNG LIVES THE HONOR, THE LUCK, THE GLORY OF ITALY
ENSURED
THE POPULATION OF THE MUNICIPALITY P. ANNO 1920
[names]

[Right plaque]
ETERNAL GLORY TO THE GENEROUS
WHO IMMOLATED THEMSELVES FOR THE FREEDOM OF ITALY
LET THERE BE EVERLASTING GRATITUDE
OF THE NEW GENERATIONS TOWARDS THOSE BRAVE
PERENNIAL FLAME FEEDING
OF CIVIL VIRTUES
SEPTEMBER 18, 1910