Nyon is first mentioned around 367-407 as civitas Equestrium id est Noiodunus (in der "Notitia Galliarum"). In 1236 it was mentioned as Neveduni and in 1292 as Nyons.
Pre-Roman settlements
A few, scattered neolithic items were discovered in the 19th Century. North of the city some bronze rings and the ruins of a Bronze Age settlement were discovered.
Noviodunum
It was founded by the Romans between 50 and 44 BCE under the name of Colonia Iulia Equestris or Colonia Equestris Noiodunum, the urban center of which was called Noviodunum. It grew to be one of the most important Roman colonies in modern-day Switzerland, with a forum, a basilica and an amphitheater that was discovered only recently, in 1996, when digging for the construction of a new building.
At Roman contact, the country round the town was held by the Helvetii. The town's importance is reflected in its numerous mentions in ancient sources. The Antonine Itinerariesplace the town on the road from Geneva to Lacus Lausonius (near Lausanne). It is first mentioned by Pliny (H.N., iv. 7), and then by Ptolemy (ii. 9), who assigns it to the Sequani. Pliny and Ptolemy simply name it Equestris; and so it is named in the Itineraries. On some inscriptions it is called Civ. Equestrium (short for Civitas Equestrium), and Col. Julia Equ. (short for Colonia Julia Equestris) from which some have concluded that it was founded by Julius Caesar. In the Notitia it is called Civ. Equestrium Noiodunum (short for Civitas Equestrium Noiodunum). The district in which Nyon stands is called Pagus Equestricus in a document of the year 1011; and it is said that the people of the country as of the 18th century still called this district Enquestre. (D'Anville, Notice, &c.; Walckenaer, G�ographie, &c., des Gaules, vol. ii. p. 316.)
Noviodunum was part of a loose network of settlements that radiated out from Lugdunum (modern Lyon, France) and helped to control the Rhone Valley
