Maastricht was important from medieval times, being the site of the lowest bridge across the river Maas (or Meuse). The town was strongly fortified in the 13th century, but new walls were built in the 14th century when the town had outgrown the previous defences.
These walls were modified for artillery by the construction of demi-lunes in front of them and by heaping earth against the medieval walls to strengthen them. The defences of Maastricht gradually evolved and hornworks were constructed in front of the demi-lunes to give the defences more depth. De Wijk, the suburb that grew up on the east bank of the river, was given full bastioned defences in the mid-17th century. Several redoubts were constructed on a large island in the river adjacent to the town to guard against river-borne attacks.
Maastricht was taken by Vauban in 1673, the siege in which he first used his system of parallels. Vauban improved the fortifications, work which was continued by Dutch engineers throughout the 18th century. The relief map depicts the town in 1752.