Centralization in the end defeated itself. The clerks of the central ministries were by no means proof against corruption and would, for a consideration, draft and submit illegal petitions to their chiefs. The ministers of the comitatus themselves, even if they were incorruptible--and they were, it would appear, often susceptible to influence and bribes--found it difficult to keep a check on the vast mass of business which passed through their hands. The emperor himself, snowed under with papers, could not examine every document submitted to him. He regularly threatened with penalties the clerks who prepared illegal rescripts and sometimes the ministers who submitted them. But he openly admitted his impotence by declaring invalid in advance any special grants in contravention of the law, even if they bore his own signature.
(A.H.M. Jones, The Decline of the Ancient World, p.153)