I'm using this principle in my Burning Wheel game. For example, one of our protagonists is Lord Alain Fitzroy, bastard brother of Queen Rowena of the Lakes. Rowena rules Fournemouth, one of the four mannish kingdoms. Now that my players have added her to the game, I can work my GM magic on this character. She needs to be interesting, with depth, with flaws and terrors, with connections. So let's turn to history.
The ever wonderful and terrifying Elizabeth I of England. Never married but often pursued. A brilliant mind from youth. Attacked by religious authorities but refraining from persecuting. Monarch in command of one of the great powers of Europe, yet able to foster the cultural growth that included Shakespeare.
That's my inspiration for Queen Rowena of the Lakes.
But let's put boundary around this. Although Elizabeth was many things, that doesn't mean Rowena is all those same things. As GM, I can cherry-pick what I need from Elizabeth without needing to bring all of it. Fournemouth has the prosperity and power of England, and has good relations between the state and the mystical. Fournemouth has a significant naval presence in the Keon Sea. Rowena rules over all of this.
And Rowena is the centre of conspiracy. In this game, Lord Fitzroy believes that there is a conspiracy against her and he will uncover it. Rowena has attended the executions of people found guilty of treason, adding weight to the feeling of suspicion in the game. This is the aspect of Elizabeth that I draw on for the larger plot, keeping the players moving.
Around the edges, though, is her unmarried status. The setting is patriarchal (ugh... medieval Europe...) but she resists. The suitors and the lords and the other kings and the advisors are all kept at bay by her choosing. She, like Elizabeth, is a woman of intellect and power, and marriage would only dilute it.
Let's see how things transpire with an Elizabeth on the throne.
