If you're looking for anime similar to Saiunkoku Monogatari 2nd Series, you might like these titles. All recommendations are made by Anime-Planet users like you!
Awayuki Himeno is a normal schoolgirl who is in a bind: her father’s remarriage yielded two new cruel stepsisters, and to top it off, she meets seven men who call themselves Liefe Knights. They reveal to her that she's a Pretear, someone who can lend powers to them when their powers aren’t enough to defeat the evil creatures called mayouchuu. Now, she has to fight the ambitious Fenrir, whose only purpose is to leech the life force from all living beings. Can Himeno save the world and find a way to deal with her growing feelings for one of the Liefe Knights?
Both Hakuouki and Saiunkoku are stories about strong female characters who are surrounded by various male characters who are historical figures. They take place in two totally different time periods, but both protagonists similarly encourage and assist the characters around them. Hakuouki does lean in a darker, supernatural direction with less romance, but I think fans of Saiunkoku would enjoy it nonetheless.