Vertical vs Horizontal Quill?

I have heard it said a few times that holding a quill vertically, like a pen, is an older style than holding it horizontally, like a whisk. To me, horizontal feels very straining in my wrist due to the strumming motion, whereas vertical feels like it is mostly engaging my forearm and not my wrist, so it is more comfortable. I am wondering which style others prefer, and am also wondering if it is true that a vertical hold on the quill is older than a horizontal hold. If this is true I am wondering if anyone has any insight into why the horizontal hold may be preferable. 
Thanks
Nate