Utrecht is a central Dutch city with a long history. With 250,000 inhabitants it's the fourth largest city in the Netherlands. The history of the city goes back to 47 AD when the Roman emperor Claudius ordered his general Corbulo to build a defenseline along the river Rhine whitch was the northern most border of the empire. One of the strongholds along the river was build at a crossing in the river and was called Traiectum . In the local language this became Trecht, Uut-Trecht and later Utrecht. On the place where once the castellum stood now stands the Domchurch built in the 13th century.