There has been some earlier investigation on this. The structure on the triangular points is indicative of what is called an Eastern Crown. Other historical examples use different ornamentation.

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(3 hours ago)Koen G Wrote: You are not allowed to view links. Register or Login to view.Although I foresee some issues with retracers

There is no such issue here.  That crown was definitely added by the last Retracer on blank vellum. 

All the best, --stolfi