Though there was, of course, that one book that told a history he would rather no one read just now. He could not afford the shadow of the second Imperium to hang over his latest ventures, so this he did not mention.

‘All eyes must be on the future,’ Guilliman continued. ‘One version of the past is in that library, another is in the heads of men. The closing of the doors was symbolic, but powerful. It seals both versions of the future away for now. I prepare, Mathieu. When this crisis is passed, perhaps something of my father’s dream might be realised, though we have a long way to climb. If we are lucky, when I reopen the doors to the Library of Ptolemy, those who enter in might finally understand what they read.’

The primarch sighed. ‘I will be honest with you, so listen. You are privy to matters I do not readily share. I see that in the period following the Great Heresy War I was too focused upon the reformation of the Legions, trusting to the council my father created to govern wisely. My optimism was misguided. This terrible future I find myself in is my fault as much as anyone else’s. Now I have concluded my revisions of the Codex Astar­tes, I have begun work upon a new book. This book I shall call the Codex Imperialis. In it I shall set down the principles of good governance long denied our species. Compiling an accurate history is only the start of the process.’

‘You do this while conducting this war?’ said Mathieu in disbelief.

‘I have few of the powers your priesthood ascribes to me, Mathieu, but I do have other abilities. I was made to accomplish many goals at once.’

‘Truly the Emperor was wise in creating one such as you.’ The unwelcome taint of awe stole into the priest’s face.

‘Not as wise as you think,’ said Guilliman, unable to keep the bitterness from his voice. ‘I was one of twenty. Two failed. Half the rest turned on my father. The Emperor is not infallible, nor am I.’ A blasphemy intended to provoke the priest. A cheap tactic. Mathieu was thankfully unmoved.

‘Yes,’ Mathieu smiled serenely. ‘But in your holiness, you did not turn.’

‘I am not holy,’ said Guilliman. ‘Worship the Emperor, if you must, but I am not deserving of your praise, nor will I accept it.’

‘I have heard some of your beliefs,’ said Mathieu. ‘When first awoken, you insisted upon something called the Imperial Truth?’

Guilliman looked away, irritated, reminded of old lies. He had been rash to voice his objections to the Ecclesiarchy in those early days after his awakening. It had taken him time to recover the full measure of his wits, and he had been alarmed by what he found.