Gasparino Barzizza of Bergamo, a humanist educator and university professor of rhetoric at Padua and Milan in the early fifteenth century, has come down to us chiefly as a pioneer expounder of Ciceronian eloquence, the man to whom the precious old manuscript of Cicero's complete rhetorical works was confided in 1421 for transcription and divulgation. For centuries, however, his considerable contribution to Seneca studies made before this date has been almost totally neglected. But for a few excerpts from his commentary on Seneca's Letter 1 to Lucilius, tucked away in Francesco Novati's footnotes to a letter of Coluccio Salutati, nothing substantial from these commentaries and their introductory material has to my knowledge ever been printed. Judging from the scanty literature on Barzizza, one is forced to conclude that the content of these commentaries has not even been examined. Still worse, the only biography of Barzizza written in the twentieth century says they are lost. Yet Gasparino Barzizza emerges from these commentaries as a leading Seneca scholar of early fifteenth-century Italian humanism. He was the central figure of Seneca studies while at Padua, a university town with a tradition of interest in Seneca stretching back to Lovato Lovati and Albertino Mussato and the revival of Senecan tragedy, and continuing with Sicco Polenton and his Life of Seneca. As part of the introductory material to his Seneca commentaries, Barzizza wrote the first humanist Latin biography of Seneca using Tacitus, and developed more fully than anyone before him the image of Seneca as a religious dissimulator, calling him for the first time a ‘Nicodemus.’ In a sadly mutilated and anonymous form, it can now be shown, Barzizza's life of Seneca was the only one printed in several early editions of Seneca's works, including the 1515 and 1529 ones edited by Erasmus, and later mistakenly attributed to Sicco Polenton. Erasmus' caustic prefatory remarks on deformers of Seneca that characterize his 1529 edition are aimed, it can also be shown, at Barzizza. Barzizza's lengthy commentary on the controversial opening of Seneca's Letter 1 to Lucilius, a set piece in its own right, stands at the centre of a dispute very much alive in his own time, in which Petrarch and Salutati participated before him, and Pier Candido Decembrio, his brother Angelo, and Leonello d'Este, Duke of Ferrara, participated after him, not to mention Erasmus himself.