Stylized map of the medieval city of Maastricht, the Netherlands, showing the late Roman castrum and the supposedly early Medieval fortifications (9th/10th c.). The Roman castrum has been excavated almost entirely; the Carolingian fortress around the church and monasterium of Saint Servatius is hypothetical. 1.Roman bridge · 2.Roman castrum · 3.Via Regia · 4.Carolingian fortress · 5.Wyck