The Arbalète sauterelle type A allowed bombs to be thrown into trenches beginning what was called what?
Trench warfare Trench warfare is a type of land warfare using occupied fighting lines consisting largely of trenches, in which troops are significantly protected from the enemy's small arms fire and are substantially sheltered from artillery. The most famous use of trench warfare is the Western Front in World War I. It has become a byword for stalemate, attrition, sieges and futility in conflict.
Fortified Position of Namur The fortified position of Namur ("position fortifiée de Namur" (PFN)) was established by Belgium following World War I to fortify the traditional invasion corridor between Germany and France through Belgium. The position incorporated the fortress ring of Namur, originally designed by Belgian General Henri Alexis Brialmont to deter an invasion of Belgium by France. The old fortifications consisted of nine forts built between 1888 and 1892 on either side of the Meuse, surrounding Namur. In the years immediately prior to World War II the forts were modernized to address shortcomings exposed during the 1914 Battle of Liège and the short siege of Namur. While the Namur defenses continued to nominally deter France from violating Belgium's neutrality, the seven upgraded forts were intended as a backstop to the fortified position of Liège, which was designed to prevent a second German incursion into Belgium on the way to France. The neutrality policy and fortification programs failed, and the Namur forts saw brief combat during the Battle of Belgium in 1940.