I only call it "r" as a visual reference. I don't interpret it as an "r" in the sense we know it. It's simply easier to say "r with a tail" or "c with a tail" when referring someone to a picture of the character.
In Latin it's not an "r" at all. It's a full word when it stands alone and a syllable when included with other text. I have an article on the "leaning r" and its visual relationship to Latin abbreviations.
Your red line is a good visualization of what was probably the course of events. I assume from your comment that you agree the letters were later added. May I also assume you see them as a different hand? I'm pretty sure they are but I am curious whether others think so too.
In Latin it's not an "r" at all. It's a full word when it stands alone and a syllable when included with other text. I have an article on the "leaning r" and its visual relationship to Latin abbreviations.
Your red line is a good visualization of what was probably the course of events. I assume from your comment that you agree the letters were later added. May I also assume you see them as a different hand? I'm pretty sure they are but I am curious whether others think so too.