This has taken some weeks to read ~ i remember sitting in the grounds of the Plas in the sunshine reading it, two or three times, and it's a month since we had that kind of weather, having just finished the wettest April on record in these Isles ~ but that is because of its density, detail, and interest to me rather than any implication of avoiding it on my part.
Ullmann has taken one of my real interests and developed it, showing both how the theories of government in the Middle Ages developed from and supported the practice of governing in Antiquity and the Middle Ages, and how the modern world is itself a development from the Middle Ages ~ a point dear to my heart, and forgotten or, more possibly, never learned or, even more likely, actively ignored, by the political classes in this country today.
Much there was here that i did not know previously, despite my supposed study of Mediæval times, and it was fascinating to watch the growth, as Ullmann showed it, of the over-arching sovereignty of the Bishop of Rome, both over the Church and the secular rulers of most of Western Europe. I had not realised that the Popes had such a positive programme of increasing their power; i had assumed that they wanted to but not that they actually planned it and used theology and philosophy to actively promote their programme. Also interesting is the point Ullmann makes that countries (primarily England) with a feudal structure were less affected by the top-down view of sovereignty which the Popes attempted to impose (quite successfully), as they already had a form of bottom-up permission for rule; i had not fully understood previously the almost complete difference which feudalism made to the history of the British Isles. Altogether, this was one of the more interesting and educational books i have read in some time; good choice to pick it up on a market stall.