Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
He alone had the right of publicly addressing the burgesses, and it was he who kept the keys of the public treasury. He had the same right as a father had to exercise discipline and jurisdiction. He inflicted penalties for breaches of order, and, in particular, flogging for military offences. He sat in judgment in all private and in all criminal processes, and decided absolutely regarding life and death as well as regarding freedom; he might hand over one burgess to fill the place of a slave to another; he might even order a burgess to be sold into actual slavery or, in other words, into banishment. When he had pronounced sentence of death, he was entitled, but not obliged, to allow an appeal to the people for pardon. He called out the people for service in war and commanded the army; but with these high functions he was no less bound, when an alarm of fire was raised, to appear in person at the scene of the burning.
As the house-master was not simply the greatest but the only power in the house, so the king was not merely the first but the only holder of power in the state. He might indeed form colleges of men of skill composed of those specially conversant with the rules of sacred or of public law, and call upon them for their advice; he might, to facilitate his exercise of power, entrust to others particular functions, such as the making communications to the burgesses, the command in war, the decision of processes of minor importance, the inquisition of crimes; he might in particular, if he was compelled to quit the bounds of the city, leave behind him a "city-warden" (-praefectus urbi-) with the full powers of an -alter ego-; but all official power existing by the side of the king's was derived from the latter, and every official held his office by the king's appointment and during the king's pleasure.
All the officials of the earliest period, the extraordinary city-warden as well as the "leaders of division" (-tribuni-, from -tribus-, part) of the infantry (-milites-) and of the cavalry (-celeres-) were merely commissioned by the king, and not magistrates in the subsequent sense of the term. The regal power had not and could not have any external check imposed upon it by law: the master of the community had no judge of his acts within the community, any more than the housefather had a judge within his household. Death alone terminated his power. The choice of the new king lay with the council of elders, to which in case of a vacancy the interim-kingship (-interregnum-) passed.
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Reference address : https://www.ellopos.net/elpenor/rome/1-05-original-constitution-rome.asp?pg=11