The fundamental charter of the English commonwealth under the protectorship of Cromwell, had been the instrument of government, drawn up by the council of officers in December 1653, and approved with modifications by the parliament of the next year. It was now changed to the petition and advice, tendered to him by the present parliament in May 1657, which made very essential innovations in the frame of polity. Though he bore, as formerly, the name of lord protector, we may say, speaking according to theoretical classification, and without reference to his actual exercise of power, which was nearly the same, that the English government in the first period should be ranged in the order of republics, though with a chief magistrate at its head; but that from 1657 it became substantially a monarchy, and ought to be placed in that class, notwithstanding the unimportant difference in the style of its sovereign. The petition and advice had been compiled with a constant respect to that article, which conferred the royal dignity on the protector;[450] and when this was withdrawn at his request, the rest of the instrument was preserved with all its implied attributions of sovereignty. The style is that of subjects addressing a monarch; the powers it bestows, the privileges it claims, are supposed, according to the expressions employed, the one to be already his own, the other to emanate from his will. The necessity of his consent to laws, though nowhere mentioned, seems to have been taken for granted. An unlimited power of appointing a successor, unknown even to constitutional kingdoms, was vested in the protector. He was inaugurated with solemnities applicable to monarchs; and what of itself is a sufficient test of the monarchical and republican species of government, an oath of allegiance was taken by every member of parliament to the protector singly, without any mention of the commonwealth.[451] It is surely, therefore, no paradox to assert that Oliver Cromwell was _de facto_ sovereign of England, during the interval from June 1657, to his death in September 1658.