The Austrian Constitutional Court, in proceedings litigated by ECSOL-member Helmut Graupner, by a judgment of 4 December 2017
a) opened up marriage for same-gender couples and
b) opened up registered partnership for opposite-gender couples 
(both from 1 January 2019)

The Austrian Constitutional Court (the first and oldest constitutional court in the world) is the first court in Europe to turn down a marriage ban for same-gender couples. Accordingly Austria is the first European country to recognize marriage equality for same-gender couples as a fundamental human right. All the other European states with marriage equality introduced it the political way.

The judgment (in German and English)