The hand grenade has a long history dating back to the earliest days of siege warfare. Once this type of fighting ceased they seem to have fallen into disuse. Their comeback would seem to have been in the American Civil War when trench warfare appeared on the battlefield. They really burst onto (pun intended) the scene during WWI when trench warfare became the norm. It was at this time, incidentally, gambling from the trenches took on the form of a game called Crown and Royal. While the technology has evolved to the online casino in gambling, grenades haven't evolved greatly since WWII. Today they form part of the inventory of all armies.