 Judging from texts known to modern scholars, the obligational technique seems to have achieved a structured format during the thirteenth century, perhaps already in its first half. The oldest currently known dedicated treatises on the obligational technique seem to be a pair of anonymous treatises edited by L. M. de Rijk as The Emmeran Treatise on False Positio and The Emmeran Treatise on Impossible Positio. (De Rijk 1974.) De Rijk dated the treatises in his edition to the early thirteenth century, and there seems to be no reason to doubt this rough date. The rules of the technique are in these treatises almost the same as in Walter Burley’s Treatise on Obligations, which might be taken as the standard bearing treatise, written around 1302 (Green 1963; Kretzmann and Stump 1988). In terms of historical development, the obligational technique belongs to what is often called logica moderna, which built on Aristotelian logic but took clear distance from the Aristotelian texts themselves.