text: Invectives Among contemporaries he passed for one of the most formidable polemical or gladiatorial rhetoricians; and a considerable section of his extant works is occupied by a brilliant display of his sarcastic wit and his unlimited inventiveness in "invectives". One of these, published on the strength of Poggio's old friendship with the new pontiff, Nicolas V, the dialogue Against Hypocrites, was actuated by a vindictive hatred at the follies and vices of ecclesiastics. This was but another instance of his lifelong obstinate denouncing of the corruption of clerical life in the 15th century. Nicholas V then asked Poggio to deliver a philippic against Amadeus VIII, Duke of Savoy, who claimed to be the Antipope Felix V — a ferocious attack with no compunction in pouring on the Duke fantastic accusations, unrestrained abuse and the most extreme anathemas.
  Invectivae ("Invectives") were a specialized literary genre used during the Italian Renaissance, tirades of exaggerated obloquy aimed at insulting and degrading an opponent beyond the bounds of any common decency. Poggio's most famous "Invectives" were those he composed in his literary quarrels, such as with George of Trebizond, Bartolomeo Facio, and Antonio Beccadelli, the author of a scandalous Hermaphroditus, inspired by the unfettered eroticism of Catullus and Martial. All the resources of Poggio's rich vocabulary of the most scurrilous Latin were employed to stain the character of his target; every imaginable crime was imputed to him, and the most outrageous accusations proffered, without any regard to plausibility. Poggio's quarrels against Francesco Filelfo and also Niccolo Perotti pitted him against well-known scholars.
  Humanist script
  Poggio was famous for his beautiful and legible book hand. Berthold Louis Ullman identified him as the inventor of the type writing known as Humanist minuscule, which gave rise at the end of the fourteenth century to Roman type, which remains popular today.