You can see that there are 4 famillies. I guess that if they were so important they were part of high nobility. The best thing is that u write to Hungarian State Archives, or go and look into Siebmachers Wappenbuch for Hungary.
He is Archduke Karl of Austria, Prince of Hungary, though I don't think he has ever made any claim to any throne.
Archduke Karl is the eldest son of the late Archduke Otto, Crown Prince of Austria and of Hungary, himself the eldest son of the last Emperor of Austria and King of Hungary Karl I.
I just joined this site and would like to know if anyone had luck getting access to church records. I have tried numerous times to contact Pannonhalma for family records with no response. If any of you have a useful source to get such information I would greatly appreciate it. Thank you