Short answers, pulled from the story.
The word grenade derives from the French word for pomegranate, which in turn traces to the Latin granatus, meaning filled with grain. The first recorded use of the word for explosives comes from the August 1536 siege of Arles, and its first recorded use in English, as granades, dates from 1591.
William Mills, a hand grenade designer from Sunderland, patented and developed the Mills bomb at the Mills Munition Factory in Birmingham in 1915. He designated it the No. 5 and it was described as the first safe grenade. The external notched surface was designed for grip, not fragmentation, according to Mills' own notes.
Rudimentary incendiary grenades appeared in the Byzantine Empire not long after the reign of Leo III, who ruled from 717 to 741. In Song China (960-1279), soldiers created gunpowder-filled devices described in a 1044 military text as prototypes of the modern hand grenade. The first cast-iron bombshells and grenades appeared in Europe in 1467.
Spränghandgranat 07, or shgr 07, is a Swedish hand grenade developed by Ian Kinley at Försvarets Materielverk and announced in 2012 as the first major innovation in hand grenades since the First World War. It is a self-righting, jumping grenade containing approximately 1,900 balls that covers a cone 10 metres in diameter with the center about 2 metres in height.
The Union Army procured approximately 93,200 Ketchum grenades during the American Civil War. They were used in the sieges of Vicksburg, Port Hudson, and Petersburg. On the Confederate side, the Augusta Arsenal manufactured around 13,000 hand grenades between 1863 and 1865.
Reports from General Sir Aylmer Haldane, a British observer of the Russo-Japanese War, described improvised grenades being used with great effect by Russian defenders at Port Arthur. The success of grenades in trench warfare conditions prompted the Board of Ordnance to develop a practical hand grenade within two years of the 1902 declaration.