A couple of the ground rules: Schubert on the medieval and early modern disputatio

Karl Friedrich Lessing (1867)

"before the beginning of the real disputation came rules for the Tragen, [rules] that were to guarantee the inviolability of Church teaching.  Only doctors appointed to a university who had acquired the [requisite] 'licentia disputandi' were permitted to dispute freely, i.e. on a self-chosen theme.  And even they could only choose [from among] themes 'salva fide catholica'.  More than that, the disputants had to guarantee under oath, in a 'protestatio' offered at the start, [that they [(man)] meant to have discussed only 'disputative' everything that might be said in the heat of the battle and [everything that] might militate against [(gegen . . . verstoßen werde)] the doctrine of the Church, but [to have] treated nothing 'assertive'.  The integrity of church doctrine was in this way already secured by the choice of disputants, the choice of themes, and the scientifico-theoretical definition of the status of [a given (des)] statement."

"Especially significant was the ban against calling the remark of an adversary heretical, a [charge] that [(was)] could have life-threatening consequences for the accused."

     Anselm Schubert, "Libertas disputandi:  Luther und die Leipziger Disputation als akademisches Streitgespräch," Zeitschrift für Theologie und Kirche 105 (2008):  415-416 (411-442).