The Roman History · Amm. 26.1.13

And from this mode of proceeding many other expedients were adopted, all of which were fallacious, and which I think it superfluous now to enumerate. But when they were given up, Octavianus Augustus, in imitation of the Greeks, corrected these disorderly arrangements and put an end to these fluctuations, after great deliberation fixing the duration of the year at twelve months and six hours, during which the sun with its perpetual movement runs through the whole twelve signs, and concludes the period of a whole year.

Ammianus Marcellinus · translated by C. D. Yonge · 1911 reprint
C. D. Yonge translation (preface dated February 1862); G. Bell and Sons, 1911; Project Gutenberg #28587
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