The in-game description references William Wallace, who was a famous Scottish knight and revolutionary during the history of medieval Europe. Wallace's most iconic weapon was a straight sword of average length rather than a greatsword, a weapon which he wouldn't have been able to use at all since he was executed in 1305 and the sword type only coming into widespread circulation around the early 16th century.
Despite being named after the great swords of the Middle Ages, the in-game weapon is actually an early Zweihänder, or "two-hander" sword as evident by its described length of six feet and lack of specialized parrying hooks, or Parierhaken. The zweihänder was more associated historically with the German Landsknecht than with William Wallace.
It is, however, a spot-on replica of the blade wielded by Wallace in the 1995 film Braveheart, the plot and setting of which were riddled with poor background research and historical inaccuracies and should not be taken as actual fact.