The first university in Spain, the fourth in Europe, was founded in Salamanca in 1254, and among the persons mentioned in its Royal Charter to teach, one of them was an “organo teacher” (“maestro en organo”) this was a uniqueness because in the 13th century music was taught only in churches and monasteries. Its existence is not a coincidence, because this novel university replicated the way of learning in al-Ándalus, where music was taught and played outside religious life. That fact was worldwide known in 1720 when The history of Spain was published and since then, some have debated whether it was a “chair of music” and whether the “organo teacher” taught theory. Considering that in the Quadrivium the physics of sound was not independent, it could be inferred that principles of acoustics was taught there in 1254. In this paper it will be demonstrated that it is not a semantic question of interpreting words, but of interpreting them in the historical context that was written, then it can be assured that it was a professorship, and by the counterfactual in this chair of music was taught the theory of sound/music, just as it was done in al-Ándalus.