Born at Sebenico in Dalmatia in 1802, Tommaseo studied with an uncle who was a monk and then he attended a seminary, first in Split and then in Padua, and later on he studied in the Faculty of Law. He loved the classics and devoted himself passionately and successfully to their translation. The crucial encounters he had with Antonio Rosmini (who would later welcome him to Rovereto) and with Antonio Marinovich led him to classical and philosophical studies, to the extent that, after he graduated in law, he decided not to take it up as a profession, but to live instead as a journalist and writer.

After articles written for the “Giornale sulle scienze e lettere delle province venete”, he worked on various editions of texts for the publisher Antonio Fortunato Stella, whom he joined in Milan, where he also met Alessandro Manzoni. He perfected his studies of Italian language and literature and developed an idea of the moral function (in a Christian sense) of poetry (he was one of the writers for the “Antologia” of Giovan Pietro Vieusseux). He moved to Florence, where he was well received in liberal-Catholic circles and made friends with Gino Capponi and Raffaello Lambruschini. On the other hand, his disagreements with Giacomo Leopardi were well-known, caused by the impossibility of reconciling their two opposing visions of poetry and of the world in general.

The anti-Austrian views that permeated his writings for the “Antologia” came to the attention of the censors, who soon closed the journal down and forced him in 1834 to find refuge in France, where he became friends with Alessandro Poerio, another exile, and also got to know Félicité-Robert de Lamennais. During his period of exile in Paris, he published writings on education, politics and philosophy, alongside poetical texts, all imbued with a strong sense of religion.

After a period in Nantes as director of an institute of practical studies and a stay in Corsica, he was pardoned and in 1839 returned to Dalmatia. Almost immediately he moved to Venice, where he spent the next ten years. As well as various articles on philosophy, language and for special occasions, the Gondoliere printing press published the first two editions of his novel Fede e bellezza. He never gave up writing on politics, civil history and ethical education, but, because he considered the intensity of expression of the authentic popular language and poetry to be greater than that of the educated form, he published four volumes of popular songs and one volume of poetry in Serbo-Croatian.

His faith in the new Pope Pius IX and in his ability to bring about ethical change in the Church convinced Tommaseo to write to him and beg him to give up any temporal ambitions and to adopt a new religious dimension that was totally spiritual: for this he was rewarded with a personal audience.

Having made his opposition to censorship public, he was imprisoned in 1848 and then freed during the insurrection of 17 March, which led to the establishment of the Republic of San Marco, of which he became Minister of Education and ambassador to France. After the fall of the republic in 1849, he took refuge in Corfu, where he started a family. In 1854 he moved to Turin, where he obtained a teaching post in an institute of commerce and wrote a biography of Antonio Rosmini, with whom he had never lost touch. In 1859 he settled in Florence, where, together with Bernardo Bellini, he worked on the well-known Dizionario della lingua italiana, published by UTET from 1861: unfortunately he would never see its completion.

Despite serious problems with his eyesight and a financial situation that was not rosy, he continued to work to the end without respite. His output ranged from autobiographic memoirs to studies on Dante, from political writings to translations of the Gospels, from advice on elegant style to guidelines on appropriate behaviour, from civil history to poetry. He was also made a member of the Società promotrice degli studi filosofici e letterari of Terenzio Mamiani and Domenico Berti. To counter the evolutionist theories of Alexander Herzen he published ten letters on L’uomo e la scimmia, con un discorso sugli urli bestiali datici per origine delle lingue, published in Milan by the bookshop and publishing house of Giacomo Agnelli.

In his diaries Raffaello Caverni recorded two visits to Niccolò Tommaseo at his house at Lungarno delle Grazie: the first, after he had written some critical Osservazioni regarding the astronomical notes by Giovanni Antonelli for his edition of the Divina Commedia, with commentary by Tommaseo and published by Pagnoni in Milan; the second, that took place about a year later, which was a disappointment for Caverni: listening to Tommaseo denying what he had said in the past in opposition to the temporal powers of the Popes made him appreciate even more the company of simple countryfolk. Niccolò Tommaseo died in Florence in 1874, following a stroke.