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
The catastrophe of June 701,
by which army and general in Syria perished, was therefore
a terribly severe blow also for Caesar. A few months later
the national insurrection blazed up more violently than ever in Gaul,
just when it had seemed completely subdued, and for the first time
Caesar here encountered an equal opponent in the Arvernian king
Vercingetorix. Once more fate had been working for Pompeius;
Crassus was dead, all Gaul was in revolt, Pompeius was practically
dictator of Rome and master of the senate.
What might have happened,
if he had now, instead of remotely intriguing against Caesar,
summarily compelled the burgesses or the senate to recall Caesar
at once from Gaul! But Pompeius never understood how to take advantage
of fortune. He heralded the breach clearly enough; already in 702
his acts left no doubt about it, and in the spring of 703 he openly
expressed his purpose of breaking with Caesar; but he did not
break with him, and allowed the months to slip away unemployed.