15thc perception on swallowtail merlons?

[Aga Tentakulus]

   
I would say the upper part of the wall is the same age as the round tower. ca 1500.
The lower part seems older. (Roman time)
I do not know but is an assumption by the explanation of the story.
Inside the wall you can see the niches for burial urns. (Roman period).
The top is seen when you look at the wall from the outside.
Change of structure. You can just see the difference.