As an "historical" novel, The Heirs of the Kingdom uses the First Crusade as a structure or form for telling a "non-historical" story. This is the story of the faceless nobodies who live inside of history. In the case of this novel, the nobodies are the mass of the poor who, in the 11th century, were inspired to accompany the First Crusade at the urging of Peter the Hermit.
Ms. Oldenbourg does leave the reader with some sense of the pathos of the hardship, ignorance, and degradation of the historically anonymous members of the group. That is, to an extent, she involves us as fellow humans. She does this by creating fictional characters with names, minds, and relationships.
But this is only part of what she does. I think that, essentially, she presents us with an horrific image or mirror of a nihilistic or negative universe in which individuals are valueless. Her characters are important to themselves and to no one else, and often they abandon themselves to self-destruction. Their physical and spiritual degradation is relentless. In the novel's context, their lives have no historical or metaphysical value. They are born and then they are lost. This is certainly the case with the personal history of Marie or of Elie Le Grele', the two characters who were most compelling for me.
Ms. O has a fascinating gift to keep me interested in these characters in the midst of her nihilism. I do want to know what will happen to them. But my interest is in persons who are alien and act in interesting but repellant ways. I do not love or feel any warmth for them --- and this is fortunate because their lives and their passage out of sight by the book's end are bleak. I feel that negative lives, their oddness as specimens, their "unloveability" is intentional.
I feel that Ms. O enhances her special narrative power and multiplies the force of her sense of the pointlessness of life when she tells the stories of many people in a fragmentary way and intersperses the stories with, or incorporates into the stories, her descriptions of filth, starvation, sickness, privation, murder, and massacre. These descriptions plus the long rhetorical cries and rants of unidentified speakers --- a kind of chorus --- tell the reader that ultimately these interesting specimens, in the mass, do not have a chance.
Ms. O is good at presenting her characters as full members of a society or, really, a sub-class of the poor that is marked by impulsiveness and irrational views of the world. Their attitudes are expressed in emotional exaltation and guilt rather than in joy and responsibility. For example, much of the death and bestiality in the book is connected to a spirituality that is frantic, hysterical, and dependent on the emotions of the moment and, presumably, by the toll that hardship takes.
Ms. O's historical novels are compelling. I've read three of them and enjoyed each --- Destiny of Fire, The Cornerstone, and now this one. They are books that stay with me, maybe because they remind me that the world was, and still is, out of hand and that reliance on it and its rewards is not --- or had not better be --- an ultimate goal.
In closing, I'd add that the events that are the historical structure of the book did occur in the same chronology as the book's stories --- insofar as I could tell from skimming Steven Runciman's history of the First Crusade in parallel with reading Ms. O's book.