Who used the longbow?

Answer 1

Throughout most of the Medieval period, all English archers would use the longbow for war, with very few exceptions.

After several encounters with English archers, countries like Scotland and France made efforts to replicate the devastating effect of such troops, but they didn't have the same kind of society that England had, and thus could never hope to produce such large quantities of professional Longbow archers.

Most areas of Europe resorted to using crossbows which required less training to use, and were in a lot of cases more powerful, though always slower.

Answer 2

There isn't one inventor. Many different scholars worked together to create it.