As a part of Western Thrace, the territory of the Evros regional unit followed the fate of that region. At 1821, several parts of Evros region, such as Lavara and Samothrace rebelled, participated in the Greek War of Independence. It became part of Greece in 1920, when it was ceded by Bulgaria as a result of the Treaty of Neuilly-sur-Seine. Initially it was part of the Thrace Prefecture, which was subdivided in 1930. During the Greco-Turkish War (1919-1922), many Greek refugees settled in the Evros, and new towns were built, including Orestiada. The Evros river valley was flooded several times, notably in 1997, 2005, and 2006.