By the accession of Pope Leo IX in 1048, a clear distinction developed between two classes of bulls of greater and less solemnity. The majority of the "great bulls" now in existence are in the nature of confirmations of property or charters of protection accorded to monasteries and religious institutions. In an epoch when there was much fabrication of such documents, those who procured bulls from Rome wished to ensure that the authenticity of their bull was above suspicion. A papal confirmation, under certain conditions, could be pleaded as itself constituting sufficient evidence of title in cases where the original deed had been lost or destroyed.