quality:correction
Writing

Although Cicero was influenced by the Academic, Peripatetic, and Stoic schools of Greek philosophy, this work shows the influence of the Stoic philosopher Panaetius. Panaetius was a Greek philosopher who had resided in Rome around eighty years previously. He wrote a book On Duties (Greek: Περὶ Καθήκοντος) in which he divided his subject into three parts but had left the work unfinished at the third stage. Although Cicero draws from many other sources, for his first two books he follows the steps of Panaetius fairly closely. The third book is more independent, and Cicero disclaims having been indebted to any preceding writers on the subject. Michael Grant tells us that "Cicero himself seems to have regarded this treatise as his spiritual testament and masterpiece."