Four British people who say they lost their jobs as a result of discrimination against their Christian beliefs are taking their case to the European Court of Human Rights.
They include an airline worker stopped from wearing a cross and a counsellor who refused to deal with gay couples.
Nadia Eweida lost her job as a British Airways check-in clerk, while Shirley Chaplain lost her job as a nurse when they refused to remove the cross the wore as a visible symbol of their faith.
Gary McFarlane was sacked after expressing a conscientious objection to counselling homosexual couples and Lilian Ladele lost her job as a registrar because she would not officiate at civil partnerships.
British courts have repeatedly ruled against Christians whose beliefs have clashed with secular rights - especially equality for gay people, the BBC reports.
The European Court's decision is expected to take several weeks and will be seen by many as a decisive moment in a long process of what Christians claim is the marginalisation of their faith in public life.