Hero of Byzantium (or Heron of Byzantium or sometimes Hero the Younger) is a name used to refer to the anonymous Byzantine author of two treatises, commonly known as Parangelmata Poliorcetica and Geodesia, composed in the mid-900s and found in an 11th-century manuscript in the Vatican Library (Vaticanus graecus 1605). The first is a poliorketikon, an illustrated manual of siegecraft; the second is a work in practical geometry and ballistics, which makes use of locations around Constantinople to illustrate its points. The manuscript consists of 58 folios and 38 colored illustrations.