Born in Livorno in 1875, he was student of Giovanni Pascoli in his city's high school. He graduated in 1895 at the Scuola Normale Superiore of Pisa and perfected his classical philology studies in Florence. In Rome, he attended the archaeology school. In 1899, while he was a teacher at the classical high school of Lucca, he was called by Pascoli to obtain the Greek and Latin grammar tenure at the university of Messina. When he was transferred to Pisa, Mancini permanently moved in Lucca. He was a committed Mazzinian and was member of the parliament in the first years after the First World War. As President of the Committee of the National Liberation of Lucca, after the liberation, he was appointed as Dean of the University of Pisa and elected in the two successive legislatures, fulfilling the roles of town and provincial councilor for the Republican party. Author of philology studies, he nurtured interests about the history of Lucca, publishing remarkable scientific contributions and presiding over the Academy of Science, Literature and Arts of Lucca.