Foreigners made a practice of supporting their petitions with letters of commendation, either from the ambassadors of their own states, or of some other of the foreign ambassadors. The applications or petitions were not always granted, and, occasionally, conditions were attached upon which the continued validity of the privilege was made to depend. Such conditions fell into four general divisions, concerned with, first, the quality of the work to be produced, secondly (though infrequently) the speed of its production, thirdly the price at which it was to be sold, and fourthly the rights of the producers, _i.e._, publishers. As an example of the first kind can be noted the privilege granted to Benaliis, already cited, under which he is bound not to publish the works of Tartagni without those of Giustiniani, nor _vice versa_, and he must further guarantee to print the volumes in the finest style of typography and with the most correct text. The privilege given in 1494 for certain books to be issued by Matteo de Codeca, is coupled with the condition that the volumes are to be sold at a “fair price” (_pretio honestissimo_), and a similar term is used in the privilege given in 1496 to Landriano. In a certain number of the privileges, principally those of earlier date, we find the condition that the works must be published within a year from the date of the application, or must be printed at a certain rate per week. The College kept no register of the privileges issued by it other than the entries in its minutes, and it happened not infrequently, as the number of petitions increased, that exclusive privileges for the same work were granted to different applicants. Conflicts naturally arose between two publishers claiming control of the same work, but when any cases of the kind were brought up for adjudication, they were decided in favour of the privileges bearing the earliest date, providing always that the condition of publishing within a certain term had been complied with. As a result of these complications, however, the practice came to be adopted of attaching to a privilege a saving clause to the effect that it should be invalid in case any earlier privilege should already have been issued for the same work. Among other instances of such a proviso, Brown quotes that included in the privilege granted, in 1493, to Calcedonio, which closes thus: _declarato, quod hæc gratia intelligatur casu quo opera ipsa sint nova, et aliquis alius jam non cœperit illa imprimere, vel sibi promissum fuerit_. Another form, occurring in 1502, was _dummodo prius dicta volumina non fuerint impressa_.[147]