 Thus Papal bulls concerning the government of the Roman Catholic Church, being exempt from all taxation, were said to be issued by way of the Roman Curia; those of which the expedition was by way of the "Cancellaria" were the common bulls, which, after being reviewed by the Abbreviators of the greater presidency, were signed by them and by the proprietors of the "vacabili", the latter of whom received the established taxes; the bulls said to be issued secretly were those in favour of some privileged persons, e. g. the Palatine Prelates, Auditors of the Sacra Rota, and relatives of cardinals, and were signed by the Vice Chancellor, also exempt from taxation; finally, the bulls of which the expedition was said to be by way of the Apostolic Camera were those that concerned it.Because the style and the rules of the "Cancellaria" could not be adapted to these bulls, they were issued by the "Sommista", whose office Pope Alexander VI instituted and later united by Pope Alexander VIII with that of the Vice Chancellor.After Pope Leo XIII abrogated all the "vacabili" in 1901, the aforementioned modes of expedition ceased.