"Tudor" as a surname comes from the Welsh variation of the name "Theodore." It's kinda like someone having Howard, Patrick, or Johnson for a surname. Funny how patronyms stick sometimes, especially after immigration.
One of the surnames in my family is Best. That amused me to no end when I was little -- we were the Best family!
My father's mother was a Crowninshield. She always believed it was English and had something to do with heraldry -- perhaps we were royal? As it turns out, it was originally von Kronenschieldt, and our "real" surname was Richter. "Richter" comes from the German word for "judge," but I haven't found any jurists yet. :)
(Also, if she got taller and leaner over the summer, that wasn't anything drastic -- it was puberty. ;))