His order, called the Order of the Preachers, was originally designed to repress heresy and confirm the faith by diffusing Catholic doctrine and maintaining the creed in its purity.

It consisted of three sections: the Preaching Friars; nuns living in conventual retreat; and laymen, entitled the Third Order of Penitence or the Militia of Christ, who in after years were merged with the congregation of S.Peter Martyr, and corresponded to the familiars of the Inquisition.

Since the Dominicans were established in the heat and passion of a crusade against heresy, by a rigid Spaniard who employed his energies in persecuting misbelievers, they assumed at the outset a belligerent and inquisitorial attitude.

Yet it is not strictly accurate to represent S.Dominic himself as the first Grand Inquisitor.

The Papacy proceeded with caution in its design of forming a tribunal dependent on the Holy See and independent of the bishops.