The ingratitude of republics is proverbial, but while reading one of Albion Tourgee's novels I wondered where the phrase comes from. It was used fairly often by the writers of our own founding era. Machiavelli had a discussion on the subject in his Discourses on Livy. I don't remember the phrase from any of my classical reading, but that was so long ago I barely missed meeting Cicero in person.

Does anyone here know the history of the rumor that republics are any more ungrateful than, say, monarchies or democracies?