The Pannonian Basin, with the term Carpathian Basin being sometimes preferred in Hungarian literature, is a large, mainly lowland area in southeastern Central Europe, briefly described as a sedimentary basin. Under the geopolitically changed conditions created by World War I and the ensuing Treaty of Trianon, the geomorphological term Pannonian Plain was also used for roughly the same region, referring to the lowlands in the area occupied by the Pannonian Sea during the Pliocene. However, Hungarian geographers consider the term "Pannonian Plain" not only unhistorical but also topographically highly erroneous. Regarding the name as such, they are arguing in terms of ancient history, namely that the northern and eastern boundary line of the namesake Roman province of Pannonia was formed by the River Danube, thus the Great Hungarian Plain was not part of the original Pannonia province.