To be honest, I don't see how this tangent has anything to do with the reading anymore. Maybe it should be split into a new thread? Anyway, as regards the much-discussed sentence Gallos ab Aquitanis Garumna flumen, a Belgis Matrona et Sequana dividit I think something was missed, albeit a very minor point. Clearly there is ellipsis in the two clauses, as has been mentioned, but by the same token there are only two clauses, not three. Matrona and Sequana are both nominative subjects in the second clause: the et between them, and the fact that a Belgis applies to both, does not fit the pattern of hypozeugma (or whatever it's called). This means that the singular verb dividit does in fact have two subjects in the second clause, at least nominally. The reason why the verb remains singular, I believe, is because the Marne and Seine rivers are being conceived of as a single boundary. This is quite evident when you look at a map, as the Marne, which flows into the Seine, looks roughly parallel with the Seine after the confluence, whereas the Seine itself flows up from the south until it joins its tributary, then continues westward.