Tolomeo Fiadoni (1236-1327) was one of the most remarkable of medieval writers. Living to almost one hundred years of age, Tolomeo bore witness to some of the most important events of the period. He studied and travelled with Thomas Aquinas and was elected Dominican prior in Lucca and Florence. He attended the saintly Pope Celestine V during Celestine's doomed reign, lived at the papal court in Avignon, served in the households of two cardinals, and associated with the infamous Pope John XXII. At the age of eighty, Tolomeo was appointed bishop of Torcello in the Venetian Lagoon, where his superior, the Patriarch of Grado, subsequently excommunicated and jailed him. Tolomeo is known today for his major contribution to republican political thought, most notably his continuation of Thomas Aquinas's only political treatise. However, he also wrote treatises on imperial and ecclesiastical power, a commentary on the six days of creation, a massive Church history, and a European history from 1063 onward. Drawn from all known surviving sources, The Life and Works of Tolomeo Fiadoni is the first full-length study of Tolomeo's life. It discusses each of his works, and addresses numerous problems of authorship and dating. Its companion volume, The Worldview and Thought of Tolomeo Fiadoni (Ptolemy of Lucca), provides an in-depth analysis of Tolomeo's beliefs and thought.