 The Arbalète sauterelle type A allowed bombs to be thrown into trenches beginning what was called what?
Sauterelle: The Arbalète sauterelle type A, or simply Sauterelle (French for grasshopper), was a bomb-throwing crossbow used by French, and British forces on the Western Front during World War I. Sauterelle:  It was designed to throw a hand grenade in a high trajectory into enemy trenches. 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.
Trench warfare