And in it's heyday it was known as a "bowe" or chauvinistically, as an English bowe.
The term "longbow" is a fairly late term used to distinguish it from a crossbow.
What the Norman kings and their captains learnt from the Welsh campaigns was the efficacy of the Welsh light troops and archery against the Anglo-Norman heavy cavalry in difficult terrain.
Following this and similar experiences against the highly mobile Scottish incursions using light horse, the English captains made significant adjustment to their view of how they might best employ the archers available to them throughout the English counties.
This was the beginning of the end of the dominance of the use of heavy cavalry in Western Europe and marked the beginnings of the English habit of men at arms and mounted archers dismounting to fight set piece battles on foot from a strong defensive position.
The canard about "deriving from" the Welsh bow is in part derived from this experience in the field, and in part from a misreading of Geraldus, who said that the archers of Gwent were the best in Wales, not that they were the superiors or antecedents of strong English archery.
Rather than rely upon puerile websites that trot out the same old nonsense over and again, I would recommend that you go to a more intelligent source for an overview of the facts.
The Yale University Press "English Monarchs" series in paperback, particularly Edward 1 and Henry V (Agincourt) are as good a place as any to start.
The books on the Henrys, I & II are very good on the Angevin building of Anglo -Norman military organisation.
These are also very sound on the social and economic context.
For Edward 111 (Dupplin Muir, Halidon Hill, Sluys, Poitiers and Crecy) Roger Cliffords "War Cruel and Sharp" is very good on making the case for chevauchee as a means of drawing out the French and porovking and attack on a defensive position.
Jonathan Sumption "The Hundred Years War" Vols i & ii are also recommended, though he is stronger on the use of chevauchee than on longbow specifics.
Also A W Boardman " The Battle of Towton" and Desmond Seward "The Wars of the Roses" which is an easy and interesting read.
The bibliographies of any of these contain many useful reference sources.
Rod.