On a lark I began making geneological tables for some of my Imagi-nations. That is both mapping the ancestors of the descendents of, and the interconnections between characters. Did it for Saxe-Burlap und Schleswig Beerstain down to 1900 and back to 1600. Very interesting. The lark turned into a bit of a slog as you get into the collateral branchs and then interweaving them with existing history and marriagesamong European royals. This gets especially interesting when you get into the various sub-branches and lines and especially when you start mapping out histories. Then going back and deciding where the crown perambulates from generation to generation.
It's tough, you have to keep the dates straight to make sure you don't have someone getting married before they are born, and who is contemporaries with who, and then you get into multiple marriages (I don't mean bigamy, just where one has a succession of spouses. Also have to watch out for incest and consanquinity.
For the Princess this becomes a big task when she has 12 children, all of whom survive to adult hood, have spouses and gradually infiltrate into all the dynasties. What's also interesting is getting people to "work" for what you want.
You can also get into very intersting connections. For example, the Princess is supposedly the daughter of Catherine of Hulden, who is the wife of the Prince of Saxe Burlap, a very tiny, tiny principality in Germany. We are pretty sure of that, we think, or at least that is the legal fiction. HOWEVER, while the patrimony of the Prince is established in the Ernestine line of Saxony, her mother is supposedly one of the illegitimate children of Augustus the Strong of Saxony by one of his many mistress. She (her mother) was by the way, the girl in 1730 who was part of that trick played on frederick William I and his son the future Frederick the Great, and who latter had a dalliance with the Prince, and who certainly had a Dalliance with Augustus himself (who I understand was not above incest) and Might be related to Madame Orlenska, and so forth, so while her father is technically the prince it could be also Frederick the Great, The Emperor Charles VI, (and hence a half sister to Maria Theresa, grand daughter of Augustus the Strong, Several other Saxon nobles from the little duchies of Saxony, The King of Sweden, A Prince of Persia (you didn't think Montesques prince wasn't going to write home about this did you) along with many others.
The other interesting thing is the character of the Prince of Zweibak, who's son becomes the Princess' husband and hence Prince consort. He has two "legitimate" sons. He has no "illegitimate sons" but he does 34 adopted children he has picked up along the way like some people collect Hummel figurines. The Old boy who is a military genius but quite mad, has a soft spot for children and once adopted a young girl tossed out by her fahter, AND the girls child in one swoop. His two Servants, Selim and Osmin who are allegedly Turkish Jannisaries, (but actually are Galician Jews masquerading ad Jannisaries because the Prince thinks they are and the pay is so good, try and shepherd him along and prevent him from being waylaid by various mothers seeking to get their child "adopted". It's become quite a cottage industry around the Prince's Country Estate of Sturmunddrang, and there are published maps of the Prince's usual routes when he goes out and about where young mothers feel it's the best spot to ambush the prince and present their petition to him, which petition is also drawn from a list of the most heart-rending tales. Selim and Osmin have gotten so tired of this they just ask the number of the tall tale from the list rather than asking to hear it.
But the geneologies are fun. Makes you see how complicated these things are in real life.