Europe’s top rights court told Russia on Tuesday it must recognise same-sex marriages, in a ruling likely to have an impact on many other member countries of the Council of Europe.

The European Court of Human Rights sided with three gay couples who had asked for the recognition of their relationships but were denied by Russian authorities. Other countries such as Poland, Ukraine and Hungary also do not extend marriage-like rights to same-sex couples.

The ruling states that countries have an obligation to make the legal protections of marriage available to same-sex couples.

Less than 15 years ago, the Strasbourg-based court concluded in another landmark ruling that the European Convention of Human Rights allows for gay marriage but does not require it. Now the court claims that consensus on the issue has shifted sufficiently that it is no longer optional.

“The Convention is a living instrument which must be interpreted in the light of present-day conditions,” the judges wrote.

Of the Council of Europe’s 46 member states, 30 countries offer same-sex couples either marriage or an equal form of legal partnership. The remaining 16 offer no such legal standing for gay couples. It remains to be seen if the other 16 countries comply.