Nyon was built by the Romans between 50 BCE and 44 BCE , and was called `` Colonia Iulia Equestris '' or `` Colonia Equestris Noiodunum '' . 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 .