 The Crown had for example received a fifth of the large number of slaves taken in the recent Mixtón War, and so could not be held clean of guilt under Las Casas's strict rules.In 1548 the Crown decreed that all copies of Las Casas's Confesionario be burnt, and his Franciscan adversary, Motolinia obliged and sent back a report to Spain.Las Casas defended himself by writing two treatises on the "Just Title" – arguing that the only legality with which the Spaniards could claim titles over realms in the New World was through peaceful proselytizing.