1859 Born in Florence, Italy.
c.1875-1880 Studied in Pisa, then in Bologna under Giosue` Carducci.
1880 Published three works at age twenty-one: Versi (a collection of his own poetry), a translation of epigrams by Meleager, and Saggi su Melchior Cesarotti.
1881 Appointed professor of liceo (undergraduate-level school). Taught in schools in Lodi, Pisa, and Rome.
1887 First in competition, appointed Professor of Italian Literature at the University of Padua.
1889 Initiated the lecture series "Lectura Dantis" of Orsanmichele in Florence.
1894 Without the formalities of a competition, nominated to the Chair of Italian Literature at the University of Florence, remaining there 40 years.
1897 Married Nella Chiarini, the daughter of one of his closest colleagues, Giuseppe Chiarini. They raised four children together: Piero, Gina, Silvia, and Carlo.
1910 Elected to the Italian Parliament as Senator (life term).
1915 Son Carlo taken prisoner during World War I and kept in Austrian prisoner-of-war camp until 1917. Guido Mazzoni volunteered for duty in exchange for his son; assigned to the Alpine region as lieutenant at age 56.
1917 Promoted to captain
1918 Received awards for his bravery in battles on the front lines of the Isonzo River.
1934 Retired from the University of Florence.
1943 Died in Florence
A Brief Bibliography
Versi (Livorno: Vigo,1880).
Epigrammi di Meleagro da Gadara (Firenze: Sansoni,1880).
Saggi di critica sulle opere di Melchiorre Cesarotti (1880).
Poesie (Bologna: Zanichelli, 1881).
Poesie With preface by Giosue` Carducci (Roma: Sommaruga, 1882).
In biblioteca (Bologna, 1886).
Rassegne letterarie (Milano, 1887).
Tra libri e carte (Bologna, 1887).
Avviamento allo studio critico della letteratura italiana (Firenze, 1892). Many editions; still considered one of the best works on this topic.
Voci della vita (Roma: Sommaruga, 1893).
Il teatro della Rivoluzione (Milano, 1894).
Manuali di letteratura greca. With G. Vitelli (Firenze, 1896).
Manuali di letteratura latina. With G. Vitelli (Firenze, 1898).
Glorie e memorie dell'arte e della civilta` d'Italia (Firenze, 1905).
Letterature straniere With P. E. Pavolini (Bologna, 1906).
Poesie (Bologna, 1913).
L'Ottocento. Two volumes (Milano: Vallardi, 1911-13). Second edition published in 1934 (Milano).
Abati, soldati, autori, attori del Settecento (Bologna, 1921).
G. Parini (Firenze, 1929).
Scritti danteschi (Bologna, 1939).
Voci ed armi per l'Italia nuova (1796-1922).(Torino: Paravia, 1940).