It is said that the name comes from the presence of some hermits in the ancient times: perhaps there were some "cells" where the ascetics isolate themselves for the meditation in solitude.
According to some other opinions the name of Celle may have a connection with Celtic-Roman city of Ocelum, that has never been found yet.
Celle was mentioned in Julius Caesar's "De Bello Gallico".
This place was probably inhabited since the prehistory: in fact there are several legends about the ancient times and the most famous one concerns the construction of the Sacra di San Michele (Saint Michael's Abbey) , the symbol of Piedmont Region.

The Abbey stands on Pirchiriano's mountain, where probably some Celtic and Roman fortifications and cults were already present.
You will notice that this mountain is exactly in front of of Celle's Caprasio Mountain.
It is said that the founder of the first Sacra's small group of people was San Giovanni Vincenzo who lived in Celle as an hermit.
One day in 987, while he was in meditation, Gabriel Archangel ordered him to erect a church.
He gathered the material he needed around Celle and by his own efforts he started building the church.
At night the material that he laboriously accumulated and assembled was by miracle carried by several angels to the opposite mountain, on the top of the Porcariano's mountain ( this was its original name): a big fire started to light up the Archangel apparition while he was pointing insistently at that peak.
For this reason Porcariano's mountain ( from Pork-->Boar) was given the more propre name of Pirchiriano ( from Fire) changing its etymology from the fire of the apparition.
This is the origin of Pirchiriano according to Samuel Butler' " Alps and Sanctuaries of Piedmont and the canton Ticino " that would mean God's Fire.
The Bishop of Turin was invited to consecrate the church: while he was sleeping in Avigliana he was awoken by the shouting and screaming of people. He went out in the street and saw the fire was blazing over the mountain, surrounded by a crown of angels. When he entered the chapel he found white doves and candles inflamed, the floor was strewed by ashes, the walls covered by chrism and the altar was already built by the angels.
So he enacted it Holy as the Sinai.
That's why the Saint Michael's Archangel's Churc is calles "La Sacra" that means "The Consecrated" par excellence as it is the only one to be consecrated directly by the angelic hand and not by a Bishop.

Legends always come from some truth.
It is beyond doubt that Celle was a place for hermitage and this is proved by the number of caverns and natural refuges
These refuges were already used in the times past: the cavern where San Giovanni Vincenzo is now part of the Celle's Church.

Even in 1800 year when some renovation was done inside the church, there were some prehistoric findings such as heads of bears, boar bones, tools for the corn...
Possibly from the prehistory since San Giovanni Vincenzo, The caverns in Celle have always been cult places.
Moreover the fires on Pirchiriano's mountain may refer to the old use of making visual signalling for military and communication reasons.