What are the objects around the portrait? Especially the top corners, and the strange animal in the middle.
Why would these be put around the portrait?

![The portrait](https://en.wikipedia.org/wiki/Henry_IV_of_France#/media/File:Fran%C3%A7ois_Ravaillac.jpg)
https://en.wikipedia.org/wiki/Henry_IV_of_France#/media/File:Fran%C3%A7ois_Ravaillac.jpg