Several colonial-era convent-kitchen legends compete for credit, naming different convents, nuns, friars and even different visiting dignitaries (an archbishop in some versions, the viceroy Juan de Palafox y Mendoza in others); food historians hold there is not enough evidence to prefer one account over the others.
What would resolve this A contemporary 17th- or 18th-century convent record or eyewitness account naming one specific convent, nun or friar as the dish's inventor, rather than the anecdotal accounts collected long after the fact, would settle which legend, if any, is accurate.
OpenCulinary history / colonial Mexican archival researchMole Poblano (Wikipedia)