When my character Thomas is hurtled back in time, it’s to the real world Anglo Saxon Kingdom of Mercia, ruled by King Offa, one of the most powerful of all the pre-Norman British kings. For such an influential man, there are huge gaps in what we know about him. That may seem surprising if you’re new to the world of Dark Ages Britain, but in truth we don’t know a great deal about anyone from that particular period.

We do know that he reigned for an astonishingly long time, from 575 to 796. We also know that he was a pretty hardnosed individual, coming to power at the end of a nasty civil war, and then setting about making Mercia the dominant kingdom in Britain by whatever means he felt necessary. He was quite comfortable with using violence to get what he wanted.

On the other hand, he was far sighted, astute in trade and diplomacy, and in some ways surprisingly modern, such as including the name and portrait of his wife Cynethryth (or Cynefrith) on some of his coinage.

He was so determined to ensure his line survived him, that not only did he liquidate his rivals, he also had his son consecrated as king while he himself was still living, and appears to have gone to great lengths to make it happen.

So, a complex man, nicely summed up in the letters of Alcuin. “Never forget Offa’s fine character, his modest way of life, his concern to reform the life of the Christian people, but do not follow him in his cruel and greedy acts.”

Think of a modern day strongman dictator, making himself out to be the fountainhead of morality, cloaking himself in all sorts of imagined fine qualities, yet committing acts of appalling, ruthless violence, and you’re about there.