Less than a hundred years after the Norman conquest of Britain, young Thomas grows up in London, while Stephen and Matilda (rather endlessly) battle it out for the crown of England. By the time young King Henry takes the crown, Thomas has been trained as both a clerk and a knight, and becomes the King's Chancellor. From these beginnings the tangled web between the King and the later Archbishop of Canterbury grows.
Duggan is often described as writing 'with a fine sense of irony', or words to that effect. I don't think it's irony - healthy cynicism, more like. Duggan writes with conviction, and the story is obviously based on solid reasearch - but it remains a good story, and it is a well-written one, too. Even his descriptions of their thought processes - a writers' trick I generally dislike - are convincing. And what is more, it feels very much of their time, with an explanation of all the vassal/overlord as well as spiritual leader/king connections, plus the complicated web of power strands that bound the Kingdom; and of the mostly mental, but sometimes quite physical, battle of temporal versus religious power.
Sometimes Duggan's books can be a bit tiresome, with too much introspection by the main vharacter, but this is not one of them. It is long, and very detailed in its explanations, but the story beats true, the interactions are fascinating, and it is a very good historical novel altogether.