_praetor urbanus_, and the Princeps probably interfered (if at all) with their jurisdiction only through his control of the rulings of the praetor in Rome. We shall trace elsewhere the mode in which the extraordinary jurisdiction of one of Caesar’s delegates, the praefect of the city, came to encroach on the ordinary jurisdiction of the Roman courts. Another method of appeal springs from the principle of delegated jurisdiction. Caesar, when he cares to exercise civil jurisdiction, can perform it either personally or through mandataries, and there is necessarily an appeal from the mandatary to the higher authority, unless this authority distinctly asserts that no appeal will lie.[1829] The appeal in such a case, if it is upheld, issues not merely in the veto but in the reform of the sentence of the mandatary. Caesar may, of course, employ such delegates as he pleases. Augustus used the _praetor urbanus_ and _consulares_ for home and foreign _appellationes_,[1830] a word which in this context probably means simply “requests for cognisance” made to the Princeps. The imperial jurisdiction in matters of trust (_fidei commissa_) was delegated to consuls or to praetors.[1831] But, apart from this regular delegation, the Emperor might instruct any one to be his _judex extra ordinem_, when he did not care to take the case himself. The appeal from provincial governors was, so far as the public or senatorial provinces were concerned, the result of a conscious striving after unity of administration, although it was not wholly unconnected with Republican precedents; with respect to Caesar’s provinces, it was a direct consequence of the fact that the governors of these provinces were merely his legates, although the frequency with which the appeal was allowed shows the same striving for a centralised jurisdiction. The principle which in the early Principate regulated appeals from the public provinces was that these should come invariably to the Senate, and this principle of the dyarchy, which tended to be disregarded, was emphatically restated by Nero at the commencement of his reign.[1832] It was probably a development of a Republican custom in accordance with which certain important cases had been summoned from the provinces to Rome by the consuls and Senate (_Romam revocatio_);[1833] but this principle seems to have been now extended to include true cases of appeal as well as cases of denial of jurisdiction. When such appeals in civil matters came to Rome, it is probable that the Senate delegated the hearing of them to the consuls.