When writing my own novel, 'Dark Aemilia', I fell in love with a real historical character, Aemilia Bassano Lanyer, the first woman to be published professionally as a poet in England, and she was the main inspiration for my story. I worked hard on the plot, and on the structure of the novel, but the themes arose from her character and the way that she responded to the relevant work of William Shakespeare - the later Sonnets, which are full of pain and rage as well as passion, and 'Macbeth' (or as I should say, 'the Scottish play').
There were times while was writing the novel when I was discouraged - VERY discouraged - and it was extremely useful to have in Aemilia such a robust and determined colleague. It was impossible for me to give up when she had surmounted obstacles which were so much greater, and embarrassing to whinge when she had had to contend with the forces of Early Modern Patriarchy, and all I had to contend with was an agent operating in Agent Time (which moves very, very slowly) or a faulty washing machine. Write about someone you love, and you won't care if some readers don't like them. Write about a character who inspires and obsesses you, and getting up at 6am each day to get the words down will feel like play rather than work.
A key question here is: has human nature changed? I don't think it has in fundamental ways - all people fear death, seek pleasure, feel hungry and so on. But everything else - all the customs and assumptions - are constantly changing. In my own lifetime, social media has transformed social life and even the way we think. I think that, as with language, historical characters are a hybrid of what is intelligible to modern readers and what is plausible in terms of the period you are writing about.
It is a challenge, and not everyone will agree about the extent to which the past and the present should inform your characters. But the more you write, the more time you spend with the characters in your story, the more idea you will have about their 'voice' and their identity.
