The Battle of Poitiers was fought on September 19, 1356, resulting in the second of the three great English victories of the Hundred Years War. The eldest son of Edward III, Edward the Black Prince, destroyed the French army near Poitiers while raiding out of Bordeaux.
The result was a decisive French defeat, not only in military terms, but it was also an economic defeat: The Black Prince's capture of John II, King of France, during the battle gained him a huge chivalrous reputation and brought the French government to its knees. France would be asked to pay a ransom equivalent to twice the country's yearly income to have her king back, an impossible sum, and he would eventually die a prisoner in England.
Our Poitiers was one of the sword types that would have seen service on both sides of that conflict. Oakeshott describes the Type XV as a strongly tapering, acutely pointed blade of flattened diamond cross-section.
A14th C archer or man at arms might have carried such a sword as a sidearm together with a buckler. It is a sword with some mass, but lively and quick. Most of the mass is concentrated close to the hilt, allowing one to cut more towards the middle part of the blade with authority.
This sword would come to its own in frantic melee or a duel with bucklers.