At length Philip IV was induced, in a pragmática of February 10, 1623, to attempt some amelioration of existing conditions. Anonymous communications were to receive no attention and precision as to dates and persons was required in alleging punishment inflicted by the Inquisition. Witnesses were prohibited to testify as to common rumor unless they could allege reasons and details. Some tribunals, especially colleges, were so rigorous that they required not only proof of limpieza but also that no doubts had been expressed, whereby many families had been unjustly defamed through the malice so frequent in these matters, all of which was forbidden for the future. A significant clause pointed out that, in the early days, persons sometimes confessed to matters about which there was no other evidence and such confessions, unsupported by external proofs, were not to be prejudicial to their descendants. The practice of many persons in compiling books called "Libros verdes ó del Becerro," fabricated with no greater authority than their own malignity, was condemned, because they caused irreparable injury and injustice and disturbance of the public peace, seeing that many persons gave evidence based only on having read such books. Any one possessing books or papers calling in question the limpieza or nobility of others was therefore commanded to burn them under pain of five hundred ducats and two years of exile. Then, to place some limit on the multiplication of investigations, it was decreed that when there had been "tres actos positivos"--three positive decisions affirming limpieza or nobility--it should be deemed a proved and settled matter for the party involved and his lineal descendants, not thereafter to be called in question, provided always that the decisions were made, with full knowledge of the case by proper tribunals, which were defined to be the Inquisition, the Council of Military Orders, the Order of St. John, the four principal colleges of Salamanca, the two principal ones of Valladolid and Alcalá and the Church of Toledo.[894]