Maslow's Hierarchy of Needs
Abraham Maslow on needs is good for some writing and character motivation. I hadn't heard of this guy. The needs are very fluid and there is a lot of overlap, but they might work to drive your character's arc forward.
Safety needs are next: The need to feel secure and unthreatened.
Love and belonging is there too, in the middle of the pyramid. Again, this links into sexual needs. So a love interest would fall into this category. Indeed, if a husband of the heroine is threatened or kidnapped, it could feed into any of the other needs.
Esteem is next. Your protagonist might hurt the honor of a villain. Your heroine may suffer from low self esteem and crave praise from others as a result. Your protagonist might wreak revenge on a villain whom he had to associate with growing up, as payback for reducing himself to work alongside him, while he bullied the main character and destroyed people.
Self-actualisation. Like the Ancient Greeks, your hero has the wherewithal to be the best he can be, and he's maxed out on wisdom and self-knowledge. He tasted the fruit in the Garden, but he's made his peace with the Man Upstairs, and he's now a fully rounded man, purged of flaws. Or whatever.
EMW Tillyard's Elizabethan World Picture
Tillyard's Elizabethan World Picture. Tillyard was a lit critic and he used his picture so that modern audiences could appreciate Tudor drama. Shakespeare may have subscribed to some of Tillyard's sentiments, but really, it's a theory that was formulated in the mid-twentieth century. I would be reluctant to impose a mindset on the people back then, other than to say that God probably played a more vital and daily role.
But it's a superb, basic notion that can be applied to a character of that era - any Christian (or Abrahamic) believer, perhaps. But it could well apply to a great swathe of humanity, from the Dark Ages to the late nineteenth century and beyond.
Its hierarchy basically works like this:
Monarch (King or Queen)
Rocks and metal and bits and bobs
Everyone should know their place. Macbeth steals the throne; people on the up tend to get smacked down in Shakespeare. The idea is found everywhere, from Frankenstein to Jurassic Park. But an eighteenth century monk might hold similar views, and teach novices the same for thematic relevance in your historical fiction.
Both theories are going out of fashion, but I feel they are excellent ways to improve anyone's writing.
Anyway, that's about it. (And look up all that stuff yourself, coz I'm probably wrong on most of it.)