This history covers, more or less, the third quarter of the 4th century AD. At this time the Roman Empire was still intact but was well on the path towards splitting into West and East. Ammianus Marcellinus was directly involved in much of the history he writes, and although because of this he is not entirely disinterested, he does furnish us with a great deal of detail, and his moments of bias generally seem to be quite minor.
One thing I liked, which was more down to the translators/editors than the author himself, was that the bits omitted were made clear. Very often in history (particularly with Polybius, whose work is something of a patchwork of missing and extant pieces) the constraints of publishing mean much is omitted, but this is the first time I’ve ever seen it made plain what wasn’t in. It’s actually very helpful, and the majority are things which would be of little or no interest to me.
It’s hard to know with this sort of work how much ease of reading is down to the author and how much to the translator, but I found it easy to read.
Most of the book is concerned with the reigns of Constans and Julian, who is clearly admired by Ammianus. However, the author does not let his fondness for the Apostate prevent him from criticising him on numerous counts. Indeed, he’s a fair and balanced judge, it seems to me. Later, Valentinian (mostly criticised by the author) is praised for his work defending the empire. After each emperor’s demise a concise look at his achievements, virtues and vices follows, and there’s always a sound mixture of praise and censure.
Ammianus also appears well-informed about the military situation both regarding Gaul and the Eastern provinces (where the majority of warfare occurs at this period in history).
In short, the book is entertaining, intelligent, balanced and well worth reading. It covers perhaps the final time that the Roman Empire is fully cohesive, before it starts to part ways into West and East on a permanent basis.