As is usual with books of this nature, there’s some context set up by outlining the background (in this case the political background of 12th century England as well as William’s own personal background, the two being closely connected).
Knowledge of William’s personal history begins when he’s a very young boy, and his life is endangered. His father had surrendered him as a hostage to King Stephen during civil war, only to immediately resume fighting the King. Stephen, furious, intended to kill William, but was apparently turned from that course by the boy’s innocence (asking a guard if he could play with his spear).
And so his life was spared. It’s no exaggeration to say that if Stephen had been a more bloodthirsty or vindictive man, English history would have been very different.
William lived just past seventy years, and during that time served five kings. The book details how he grows from skilful but headstrong as a young warrior, to a wise old owl with retainers and land of his own to worry about.
During his life he rose from being the landless younger son of a warlord to guardian of the realm. Whilst exhibiting self-interest, pestering for preference and sometimes a stubborn streak, William was intensely loyal to his patrons and valued his reputation for loyalty more than all else. He was also faithful to his followers, and more forgiving than other men might have been when he was betrayed (both by King John and his own followers).
The book is very easy to read (I’m not familiar with this period of history and didn’t come across anything difficult), and the author makes occasional use of footnotes to elaborate on points. There are several maps, and two collections of photographs, as is common with this type of book.
So, what didn’t I like? There’s a fleeting reference to CE rather than AD (a pet hate). There’s also a small factual error late on, when Asbridge asserts that the Black Prince established the Order of the Garter (it was his father, Edward III, although the Black Prince was one of the founder members).
It is worth pointing out there are many biographies of William Marshal. I can’t comment on whether this is better than the alternatives, but I enjoyed the book from start to finish, and would recommend it to anyone interested in reading about this period generally or William Marshal in particular.