One of the principal struggles between the popes and the kings was the royal claim of the _pase regio_, or the right to examine papal bulls and pontifical letters and, if deemed advisable, to retain them, prohibiting their publication and therefore their execution in Spanish domains. The origin of this claim on the part of the Spanish monarchs seems to date from the period of the Great Schism, when Urban VI (1378-1389) granted such a privilege to the princes allied with him. It was not officially decreed in Spain until the early years of Charles I, when provision for the _pase regio_ in all Spanish dominions was made in a document drawn up by Cardinal Ximénez. According to this arrangement papal communications were to be examined in the _Consejo Real_, and if found to be contrary to the royal prerogative or otherwise objectionable their circulation was to be postponed and the pope asked to change or withdraw his dispositions. Usually the retention of such documents took place without giving official notice to the pope,--which in the case of a hostile pontiff would have been in any event unavailing. If the popes insisted on their point of view the royal prohibitions were nevertheless continued. If any subjects of the king resisted his will in this matter, even though they were churchmen, they might incur the penalty of a loss of goods or banishment or both, and notaries or attorneys might even be condemned to death. When Paul IV excommunicated Charles I and Philip II, the latter put into effect the _pase regio_. Unable to procure the publication of his bull in Spain, Paul IV summoned to Rome two Spanish bishops who were intensely royalist in their sympathies. Philip II protected them by retaining the papal order, so that the individuals did not learn officially of the summons. Not only in serious contests of this character but also in matters of comparatively little moment the kings exercised the right of retention,--for example, in the case of a bull of Sixtus V about the dress and maintenance of the clergy. The above are only a few instances out of many. One of the most bitter conflicts was waged by Philip II in opposition to a bull of Pius V excommunicating those who retained papal dispositions. Philip II retained this bull, and punished some bishops of Spain’s Italian domains who had published it within their dioceses. The pope threatened to put Spain under an interdict, but Philip declined to yield. The bull was never published in the peninsula, and the pope did not make use of the interdict. [Sidenote: The case of Cardinal Borja.] [Sidenote: Interference of Charles I and Philip II in matters of church reform.]