Short answers, pulled from the story.
The first recorded use of the word grenade for an explosive device occurred during the August 1536 siege of Arles by Emperor Charles V. The term itself derives from the French word for pomegranate, a fruit whose seeds resemble the shrapnel of these weapons.
Rudimentary incendiary grenades appeared in the Byzantine Empire shortly after the reign of Leo III between 717 and 741. These early devices utilized Greek fire encased in stone and ceramic jars designed to rupture and spread fire.
Grenades became standard issue munitions by the 15th century when the fleet of Alfonso the Magnanimous loaded 200,000 copper pomegranates filled with gunpowder in Barcelona in 1433. These devices were designed to explode and spray metal shrapnel, making them true ancestors of the modern fragmentation grenade.
William Mills, a hand grenade designer from Sunderland, patented and manufactured the Mills bomb at the Mills Munition Factory in Birmingham, England in 1915. This design, designated the No.5, was described as the first safe grenade featuring explosive-filled steel canisters with a triggering pin and a distinctive deeply notched surface.
The shgr 07, or Blast hand-grenade 07, was announced as the first major innovation in the area of hand grenades since the Great War in 2012. Developed by Ian Kinley at the Swedish Försvarets Materielverk, this self-righting, jumping hand grenade contains some 1,900 balls that cover a cone 10 metres in diameter with the center about 2 metres in height.