I still remember when I was having a nice cold Limoncetto with pope Sixto IV -he liked his Limoncetto- when I suggested to him to build a Cathedral ...he was so exited that he decided to go ahead. In any event the Vatican was a pretty big empty space. So, either it was a Cathedral or a parking lot. The problem with the parking lot was that there were no cars. They built the Cathedral.
Then, of course we had to name it after him (in 1470 we named things after Church personalities not politicians).
Oh if Sixto was alive... he would have called this teen idol to have a private talk with him (priests love to have private talks with teens) to clarify that it is not the Sixteenth Chapel...but Sixtine, named after him.