I had simply no idea about any of this, and there was so much to take in: the intellectual ferment of London in the 1780s, the weird and disturbing experience of being a governess in Ireland at Mitchelstown Castle (and the long-term legacy in Mary King's career), the terrifying proximity to the French Revolution, and the final years of struggle culminating in an early death.
The French revolutionary period was particularly fascinating. Maybe twenty-five years ago I read Simon Schama's Citizens, which mainly deals with an earlier stage of proceedings; by the time Mary and her entourage reached Paris, things had got very exciting and very dangerous. She was clearly seduced by the sense that all was possible, and also by a dubious American. By the time the Revolution had started decapitating feminists, Mary and her baby had got away.
The saddest part is her death, due to a partially retained placenta after her second daughter's birth; she appeared to be recovering well at first, but after a few days septicaemia had its horrible way with her. I guess that only modern antibiotics would have really solved the problem, though the medics of the day only made things worse.
Her gravestone is in Old St Pancras Churchyard in London (though she was reburied in Bournemouth years later by her grandson, Percy Shelley junior). It's close to the Eurostar terminal, and I dropped by the other week to pay my respects. An admirer had left her a Valentine card. I'm not sure that she would have appreciated it; but I did.