In Roman mythology, Silvius, or Sylvius, (Latin: Silvǐus; Ancient Greek: Σιλούιος; said to have reigned 1139–1110 BC), or Silvius Postumus, was either the son of Aeneas and Lavinia or the son of Ascanius. He succeeded Ascanius as King of Alba Longa.
According to the former tradition, upon the death of Aeneas, Lavinia is said to have hidden in a forest from the fear that Ascanius would harm the child. He was named after his place of birth, Silva being the Latin word for forest or wood.
According to Dionysius of Halicarnassus, a dispute arose on who should succeed Ascanius, either Silvius (the brother of Ascanius) or Iulus (the son of Ascanius). The dispute was decided in favor of Silvius by the people who believed that it was his right as the grandson of Latinus. Iulus was awarded the priesthood. All the kings of Alba following Silvius bore the name as their cognomen.
- Dionysius of Halicarnassus Roman Antiquities 1.70
- Neil Wright The Historis regum Britannie by Geoffrey of Monmouth II The First Variant Edition: a critical edition
- Schedel, Hartmann 1440-1514 The Nuremberg Chronicle Madison, Wisconsin: University of Wisconsin Digital Collections Center 2010
- Vergil Aeneid 6.763-766
- Dionysius of Halicarnassus, Roman Antiquities 1.70