Could it perhaps be referring to Vauban ( 1633-1707)? He was one of Louis XIV's prominent generals, and his best military engineer. Vauban developed sophisticated designs for fortresses which sometimes today are referred to as "star forts": cannon mounted along each of the walls of the points were capable of crossing fields of fire that made it difficult for an attacking army to storm it. But Vauban also developed a method of criss-cross entrenching that enabled a besieging army to slowly dig its way to a place where it could set up siege mortars and other cannon and break down the walls of the fort or force it to surrender. If the fort couldn't send out sorties and prevent that, it would finally fall. One example of this in the Seven Year's War was the Siege of Fort William Henry but I am sure there are many other examples.

I am not sure exactly when countries stopped using Vauban's fortification vs. trenches methods- maybe a specialist can say, here- obviously it could make little sense to spend huge amounts of money on a fortress that , in the end, needed to be defended by an army anyway. And you can't defeat a huge invading army with just one fortress, only inconvenience it. But forts continued to be built into the 19th century of course, especially for guarding harbors- like Ft Sumter; or to help defend borders- like the Belgian forts that impeded the German advance in 1914.