A historian friend of mine told me about the case of an ordinary medieval woman obtaining a divorce.
‘Are you serious?’ I exclaimed. ‘Look at the trouble Henry VIII had.’
‘I'll send you the journal article,’ she promised.
And it arrived in the post a few days later, the real life story of how a woman escaped a hateful husband – a medieval 'Green Card' scenario. The woman's family had paid a stranger to pretend he had married her secretly before her real marriage took place. The pair had to stand up in a church court and pretend they had fallen in love.
So I took the bones of the story and upped the pressure. I made the heroine a high-ranking lady with a dowry and I made the hero a rebel blackmailed into playing the role of lover because he was on the run from the king's men. The subplot is an echo of the main story – the unhappy Queen Isabella rebelling against the rule of her husband, the gay king, Edward II and his favourite.