Why can't I get a Union with Aragon?

[The Real Zizmon]

I'm playing as Austria and I have more development than Aragon, they have an old king with no Heir and I have WAY more prestige than them and yet a local noble still ascends to their throne.

Do I need to have more autonomy modified development than their subjects too or just the target country?

 

[Vetgirig]

Local noble ascends when a nation is at war and the old king dies without an heir.

 

[grommile]

Personal unions are not a simple "meet this transparent set of binary conditions and numeric thresholds, get a PU".

atwix has a lengthy forum thread about the mechanics of getting personal unions.

 

[R4ndy]

They leed a union over Naples, afaik you can't get a union over a senior partner peacefully.