Sebastien Vauban (1633-1707). 1841 illustration of the French military and civil engineer Sebastien le Prestre de Vauban. Vauban specialised in designing fortifications. A noticeable example of this is the Citadel in Lille, France. Vauban also pioneered methods of siege warfare. His method was to dig zigzag trenches parallel to a defending wall. The zigzag shape helped protect the trenches from attack. These trenches would be advanced until they were close enough for the attacking artillery to breach the wall. De Vauban was a humanitarian, always allowing the defenders to surrender peacefully.