Bela-Alexios lost the Byzantine succession but was named kaisar & married the empress' sister Agnes

Summary:
 
Dates:
1170 (Uncertain) 
Bela III, king of Hungary (Bela 53)
  • Though he had been destined as son-in-law for Manuel 1, this had been prevented by the rules of consanguineity, so he had been married to the empress’ sister (Agnes 17002) and made kaisar, outranking all other aristocrats (:) νόμου δὲ συγγενείας ἐμποδὼν αὐτῷ γεγονότος Kinnamos 287.2-6