The fifteenth century saw an increased output of treatises dedicated to illustrations of machines for civil and military use. These works were inspired by illustrious classical forebears, like Athenaeus, Philo of Byzantium, Vitruvius, Vegetius, etc. Among the most accomplished and earliest treatise-writers were Mariano di Iacopo, known as Taccola, and Francesco di Giorgio. These two Sienese artist-engineers compiled profusely illustrated texts where one observes the attempt to combine a revival of classical technology with the development of innovative methods and processes. Such texts ushered in a new literary genre: that of "engineers-authors". Their profound impact is attested by their widespread, long-lasting success.