- Lucretia Borgia According to Original Documents and Correspondence of Her Day
- Renaissance in Italy, Volume 1 (of 7): The Age of the Despots
- Renaissance in Italy, Volumes 6 and 7 (of 7): The Catholic Reaction
- The Civilisation of the Renaissance in Italy
- The Life of Cesare Borgia
- The Renaissance: Studies in Art and Poetry
- The Renaissance: studies in art and poetry