How far back does the rank of Grenadier go? The word is surely derived from grenade and can only have come into play since we first started hurling such devices at each other, [ not that long I`m thinking.]
Primitive hand grenades have been reportedly in use (in Europe) since around the early C18 at least.
Grenadiers have been around quite a while, as they were originally troops which specialised in siege warfare (storming breaches and such - plus using said grenades). These eventually developed into crack assault troops. If I remember correctly each batallion ended up having at least one company of Grenadiers for such purposes. But I might be wrong.
The words 'grenade' and 'grenadier' have been around for getting on for half a millennium! The first is recorded from the 1590s and the second from the 1670s.