followed the road networks, dumped sewage into the lake.
Decline of the Roman Colonia
After a long period of peace and prosperity, signs of crisis and general insecurity were increasing in the early 3rd Century. As a result of Alamanni invasions of 259 or 260 AD, the forum and the public buildings in the city were razed. The stone blocks were scattered all over the Lake Geneva region. The stones were re-used as building material, especially in Geneva, where about 300 were used in the construction of the wall. But the settlement was not abandoned. Nyon-Noviodunum, which had already lost much of its prestige and reputation was as a regional capital, now separated from Geneva. Geneva became the center and seat of the diocese which initially fought to administer the territory that had been part of the Colonia.
Medieval Nyon
During the Carolingian era, Nyon belonged to the county of Geneva. In a 926 charter, Rudolph II of Burgundy mentioned that this area was under acomes de pago Equestrico. During the Second Kingdom of Burgundy, Nyon became independent from Geneva. In 1032, Rudolf III granted Nyon to the Archbishop of Besan�on. The bishop granted Nyon to the Lord of Prangins as a fief. After 1130, Humbert de Cossonay, the Lord of Prangins, held his court in Nyon. A market was built in 1211. In 1272, the Archbishop of Besan�on confirmed Philip of Savoy's right to administer high justice in Nyon. In 1279, Aymon of Prangins unsuccessfully rebelled against the counts of Savoy, but was forced to acknowledge Savoy authority over him and Nyon.
The Castle is first mentioned in 1272, but probably dates back to the Lords of Prangins. It was rebuilt by Louis I of Savoy. The rectangular building was built in a variety of building styles. In 1463, it was extensively rebuilt. Around the same time, the square C�sar Tower or Tour de Rive (now a residence), was built to defend the city.
In 1293, Am�d�e V and his brother Louis I,
