The Netherlands, or Low Countries, possessed clearly delineated boundaries only after 1500. Still in many respects they demonstrated common traits and underwent similar development that differentiated them from surrounding countries. The social, economic and political similarities evident throughout most of the region stem from the High Middle Ages, when the Scheldt, Maas and Rhine delta area became an important center of trade. Next to Northern Italy, the Low Countries became the most urbanised and prosperous region in Europe.