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
Through this set termination of the supreme office the
practical irresponsibility of the king was lost in the case of the
consul. It is true that the king was always in the Roman commonwealth
subject, and not superior, to the law; but, as according to the Roman
view the supreme judge could not be prosecuted at his own bar, the
king might doubtless have committed a crime, but there was for him no
tribunal and no punishment. The consul, again, if he had committed
murder or treason, was protected by his office, but only so long as
it lasted; on his retirement he was liable to the ordinary penal
jurisdiction like any other burgess.
To these leading changes, affecting the principles of the
constitution, other restrictions were added of a subordinate and more
external character, some of which nevertheless produced a deep effect
The privilege of the king to have his fields tilled by task-work
of the burgesses, and the special relation of clientship in which
the μέτοικοι as a body must have stood to the king, ceased of
themselves with the life tenure of the office.