When I was a kid I remember watching an animated TV show about this posh rich British kid who played the violin and lived in like the 17th or 18th century. He wore like the kerchief tie thing and short with the long socks like from the Hamilton musical. The antagonist was like his uncle or servant who had a talking rat in his pocket. The ending theme was violin music with a song that said the kid's name but I can't remember it.
It wasn't Liberty's Kids.