Sometimes one can get confused when looking at family lines because sometimes they entertwine so many times.

Sometimes ? I admire anyone who only gets confused sometimes. I often get confused.

Family relations should be called a science; that's how confusing they are to me. And what I have learned (even drawn up on my own copies of family trees) doesn't stick: I constantly have to go back and check to make sure that I am not committing an error when I claim to know something. E.g. William being Edward's first cousin once removed: I've known that for many years, and I read up on this period all the time, yet I don't trust my memory and will always look up the relationship before I write it down again.