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
In the course of the seventh century there were gradually added to the six special departments already existing six others, viz. the five new governorships of Macedonia, Africa, Asia, Narbo, and Cilicia, and the presidency of the standing commission respecting exactions.(26)
26. Cf. IV. II. Vote by Ballot
With the daily extending sphere of action of the Roman government, moreover, it was a case of more and more frequent occurrence, that the supreme magistrates were called to undertake extraordinary military or judicial commissions. Nevertheless the number of the ordinary supreme annual magistrates was not enlarged; and there thus devolved on eight magistrates to be annually nominated--apart from all else--at least twelve special departments to be annually occupied. Of course it was no mere accident, that this deficiency was not covered once for all by the creation of new praetorships.
According to the letter of the constitution all the supreme magistrates were to be nominated annually by the burgesses; according to the new order or rather disorder--under which the vacancies that arose were filled up mainly by prolonging the term of office, and a second year was as a rule added by the senate to the magistrates legally serving for one year, but might also at discretion be refused--the most important and most lucrative places in the state were filled up no longer by the burgesses, but by the senate out of a list of competitors formed by the burgess-elections.
Since among these positions the transmarine commands were especially sought after as being the most lucrative, it was usual to entrust a transmarine command on the expiry of their official year to those magistrates whom their office confined either in law or at any rate in fact to the capital, that is, to the two praetors administering justice in the city and frequently also to the consuls; a course which was compatible with the nature of prorogation, since the official authority of supreme magistrates acting in Rome and in the provinces respectively, although differently entered on, was not in strict state-law different in kind.
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Reference address : https://www.ellopos.net/elpenor/rome/4-10-sullan-constitution.asp?pg=35