Ravenna is a fascinating town. Founded as a safe retreat for the Roman emperors when Rome became vulnerable to barbarian attacks (a little like how Venice was founded as a refuge from later barbarian attacks), and the capital for Theodoric the Gothic king who held it as a more or less independent fief under Constantinople's hegemony it became the centre for the Italian foothold of the Byzantine emperor until it was eventually taken first by the Lombards and later by the Franks under Charlemagne. It thus spent four hundred years being the meeting place for the developing Latinate culture associated with the Roman Catholic papacy and the developing Byzantine culture associated with Constantinople. This culture clash led, as so often, to learning; it was the centre for an important early medieval medical school as well as the city in which Boethius flourished (and later died).

Famous names kept appearing. As well as those above were Byzantine emperors Justinian, Leo the Iconoclast, and Irene, and others including Belisarius and Stilicho, Pope Gregory the Great , Gerbert of Aurillac and "the famous Queen Radegund" who is presumably the same as the saint celebrated in Canterbury's St Radegund's Car Park.

I found it hard going. As with many books such as this, I found that there was too much information. Ravenna is a fascinating city and there are some compelling personalities but to condense four hundred year into as many pages means that the canvas is overcrowded with incident. This happened and then this and then this; it was history as an overwhelming flood.

Furthermore, sometimes the sequencing seemed awry. For example, in chapter 28 Herrin tells us that the death of Johannicis was "monstrous" (when the emperor who ordered it is deposed) but it is not until chapter 30 that we revisit what happened and find out the manner of the death. I was frequently confused.

But in these books there are always little nuggets. I didn't realise that the Lombards were identified by their long bears (longobardi). Nor did I know that, according to the "Anonymous Cosmographer of Ravenna" "the sun does not hide behind huge mountains during the night, or sink belowe the waters of the Ocean, but returns to its seat in the East ... from Germania and Britannia, via the Baltic islands of the Fini, to the Caucasus, Scythia, Sarmatia and the Caspian Gates to Bactrian India." (Ch 27). And the iconoclasts in 726 were prompted by "a terrifying subaquatic volcanic eruption in the Segean [which] threw up a new island between Thera and Therasia ... [in which] monstrous deposits of ash and solid lava were borne to the shores of the Aegean in a tsunami" (Ch 32)

Ultimately I felt that this book failed to do justice to an absolutely fascinating period of history, with the establishment of the Christian church and the early battles for orthodoxy, with the disintegration of the Roman Empire, and with the arrival of the Islamic caliphate.