Who invented field hockey when where and why?

England, I believe.

Hockey is the oldest known stick-and-ball game (apart from Irish hurling, which dates back to pre-historic times). Historical records show that games resembling modern Field Hockey were played in various ancient civilizations, although it is not possible to know exactly when and where the game began. There are 4,000 year old drawings in Egypt of the game being played. While modern hockey appeared in the mid-18th century in England, primarily in schools, it was not until the first half of the 19th century that hockey became firmly established, the first club being created in 1849 at Blackheath in south-east London.