He wrote his most significant works during this time, including The City of the Sun, a utopia describing an egalitarian theocratic society where property is held in common.

Son of an illiterate cobbler, he entered the Dominican Order before the age of fourteen,[3] taking the name of fra' Tommaso in honour of Thomas Aquinas.

Campanella's aim was to establish a society based on the community of goods and wives, for on the basis of the prophecies of Joachim of Fiore and his own astrological observations, he foresaw the advent of the Age of the Spirit in the year 1600.

[7] Even from the confinement of the jail, Campanella managed to influence the intellectual history of the early seventeenth century, by maintaining epistolary contacts with European philosophers and scientists, Neapolitan cultural circles, and Caravaggio's commissioners.

In my opinion Your Excellency should write to the Grand Duke of Tuscany, that since they are putting Dominicans, Jesuits, Theatines, and secular priests who are against your books in this council, they should also admit Father Castelli and me.Campanella was finally released from prison in 1626,[3] through Pope Urban VIII, who personally interceded on his behalf with Philip IV of Spain.

Campanella put into effect the natural magic practices described in his short treatise De siderali fato vitando (How To Avoid the Fate Dictated by the Stars).

With the aid of Cardinal Barberini and the French Ambassador de Noailles, he fled to France, where he was received at the court of Louis XIII with marked favour.

[13] The historian John Headley described Campanella as "a man who strove to destabilize the regnant forces of what he identified as tyranny, sophistry, and hypocrisy and to shake the world into a new order.