Melk Abbey and Passau

The bishops were very powerful and had the property to prove it.

Melk Abbey

Passau Cathederal

The bishop's residence - extra painted windows make it look more grandiose

All this is paid for by taxes.  Even today in Austria you pay means tested tax to the church of your religion through the government tax dept.  If you don't you the catholic church sends you a letter saying you are excommunicated, then you cannot you into a church, be a god parent, be buried in a church cemetery, etc.