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
The wide steppes destitute of hills and trees, which stretch to the north of the Black Sea, of the Caucasus, and of the Caspian, are by reason of their natural conditions--more especially from the variations of temperature fluctuating between the climate of Stockholm and that of Madeira, and from the absolute destitution of rain or snow which occurs not unfrequently and lasts for a period of twenty-two months or longer--little adapted for agriculture or for permanent settlement at all; and they always were so, although two thousand years ago the state of the climate was presumably somewhat less unfavourable than it is at the present day.(6)
6. It is very probable that the extraordinary drought, which is the chief obstacle now to agriculture in the Crimea and in these regions generally, has been greatly increased by the disappearance of the forests of central and southern Russia, which formerly to some extent protected the coast-provinces from the parching northeast wind.
The various tribes, whose wandering impulse led them into these regions, submitted to this ordinance of nature and led (and still to some extent lead) a wandering pastoral life with their herds of oxen or still more frequently of horses, changing their places of abode and pasture, and carrying their effects along with them in waggon-houses.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/4-08-east-king-mithradates.asp?pg=15