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
Reform of the Centuries
According to the order of voting hitherto followed in the centuriate comitia, although the freeholders were no longer--as down to the reform of Appius Claudius(59) they had been--the sole voters, the wealthy had the preponderance.
59. Cf. II. III. The Burgess-Body
The equites, or in other words the patricio-plebeian nobility, voted first, then those of the highest rating, or in other words those who had exhibited to the censor an estate of at least 100,000 -asses- (420 pounds);(60) and these two divisions, when they kept together, had derided every vote. The suffrage of those assessed under the four following classes had been of doubtful weight; that of those whose valuation remained below the standard of the lowest class, 11,000 -asses- (43 pounds), had been essentially illusory.
60. As to the original rates of the Roman census it is difficult to lay down anything definite. Afterwards, as is well known, 100,000 -asses- was regarded as the minimum census of the first class; to which the census of the other four classes stood in the (at least approximate) ratio of 3/4, 1/2, 1/4, 1/9. But these rates are understood already by Polybius, as by all later authors, to refer to the light -as- (1/10th of the -denarius-), and apparently this view must be adhered to, although in reference to the Voconian law the same sums are reckoned as heavy -asses- (1/4 of the -denarius-: Geschichte des Rom. Munzwesens, p. 302).
But Appius Claudius, who first in 442 expressed the census-rates in money instead of the possession of land (Cf. II. III. The Burgess-Body), cannot in this have made use of the light -as-, which only emerged in 485 (Cf. II. VIII. Silver Standard of Value). Either therefore he expressed the same amounts in heavy -asses-, and these were at the reduction of the coinage converted into light; or he proposed the later figures, and these remained the same notwithstanding the reduction or the coinage, which in this case would have involved a lowering of the class-rates by more than the half.
Grave doubts may be raised in opposition to either hypothesis; but the former appears the more credible, for so exorbitant an advance in democratic development is not probable either for the end of the fifth century or as an incidental consequence of a mere administrative measure, and besides it would scarce have disappeared wholly from tradition. 100,000 light -asses-, or 40,000 sesterces, may, moreover, be reasonably regarded as the equivalent of the original Roman full hide of perhaps 20 -jugera- (I. VI. Time and Occasion of the Reform); so that, according to this view, the rates of the census as a whole have changed merely in expression, and not in value.
According to the new arrangement the right of priority in voting was withdrawn from the equites, although they retained their separate divisions, and it was transferred to a voting division chosen from the first class by lot. The importance of that aristocratic right of prior voting cannot be estimated too highly, especially at an epoch in which practically the influence of the nobility on the burgesses at large was constantly on the increase.
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Reference address : https://www.ellopos.net/elpenor/rome/3-11-government-governed.asp?pg=70