A British Airways employee suffered discrimination at work over her Christian beliefs, the European Court of Human Rights has ruled.
She took her case to the European Court of Human Rights after BA made her stop wearing her white gold cross visibly.
Judges ruled that the rights of three other Christians had not been violated by their employers.
They had brought cases against the government for not protecting their rights but ministers, who contested the claims, argued that the rights of the employees were only protected in private.
Ms Eweida, 60, a Coptic Christian from Twickenham in south-west London, told the BBC she was "jumping with joy" after the ruling, adding that it had "not been an easy ride".
It said Ms Eweida did not attend work for a period of time in 2006 while an internal appeal was held into her refusal to remove her cross and she remained a British Airways employee.
Prime Minister David Cameron said he was "delighted" that the "principle of wearing religious symbols at work has been upheld", adding that people "shouldn't suffer discrimination due to religious beliefs".
The other cases involved nurse Shirley Chaplin, 57, whose employer also stopped her wearing necklaces with a cross, Gary McFarlane, 51, a marriage counsellor sacked after saying he might object to giving sex therapy advice to gay couples, and registrar Lillian Ladele who was disciplined after she refused to conduct same-sex civil partnership ceremonies.
The four had made individual applications to the ECHR after losing separate employment tribunals but their cases were heard together.
They argued their employers' actions went against articles 9 and 14 of the European Convention on Human Rights, which protected their rights to "freedom of thought, conscience and religion" and prohibited religious discrimination.
BBC religious affairs correspondent Robert Pigott says the judgements suggested that although people are entitled to hold religious views, that right is severely limited in the workplace when it comes into conflict with the rights of other people.
Our correspondent says the judgement also hands considerable discretion to employers to set reasonable policies and then insist that employees follow them whatever their religious beliefs.
Ms Ladele was disciplined by Islington Council, in north London, after saying she did not want to conduct same-sex civil partnership ceremonies. Her lawyers said the service could have been performed by other employees who were prepared to carry them out.
The Christian Institute, which backed Ms Ladele's case, said it was "disappointed" by the ruling, adding it showed Christians with traditional beliefs about marriage were "at risk of being left out in the cold".
Mr McFarlane, a Bristol relationship counsellor, worked for the Avon branch of national charity Relate but was sacked for gross misconduct in 2008 after saying on a training course he might have an objection to discussing sexual problems with gay couples.
He told BBC News that the decision taken by European judges in his case was "a regrettable judgment" for all faiths, not just Christians.
Ms Chaplin, from Exeter, was transferred to a desk job by Royal Devon and Exeter NHS Trust Hospital for failing to remove a confirmation crucifix on a small chain, which she had worn to work for 30 years.
She said she thought British Christians would be "devastated" by the ruling.
The BBC's Robert Pigott said the European judges had decided that agreed health and safety concerns outweighed her religious rights.
Ms Chaplin and Mr McFarlane said they planned to ask for their cases to go to appeal to the Grand Chamber of the ECHR.
Communities Secretary Eric Pickles said he was "very pleased" with the ruling on Ms Eweida.
"I thought it was wrong that BA banned people wearing religious symbols, I'm pleased that they changed that long before this court judgement.
He added: "But clearly if you're delivering a service to the public you shouldn't be able to discriminate against somebody on grounds of their sexual orientation. We live in a country where everybody's treated equally."
The Archbishop of York, Dr John Sentamu, said: "Christians and those of other faiths should be free to wear the symbols of their own religion without discrimination. Christians are not obliged to wear a cross but should be free to show their love for and trust in Jesus Christ in this way if they so wish."
He said the Equality Act 2010 "encourages employers to embrace diversity - including people of faith", adding: "Whether people can wear a cross or pray with someone should not be something about which courts and tribunals have to rule."
Meanwhile, Keith Porteous-Wood, of the National Secular Society, said: "Religious people who feel elements of their job go against their conscience can always find employment that better matches their needs. That is true religious freedom."
Shami Chakrabarti, director of human rights group Liberty, said the judgment was "an excellent result for equal treatment, religious freedom and common sense".
She said British courts had "lost their way" in Ms Eweida's case and "Strasbourg has actually acted more in keeping with our traditions of tolerance."
"However the court was also right to uphold judgments in other cases that employers can expect staff not to discriminate in the discharge of duties at work," she added.
Andrew Copson, chief executive of the pro-secular British Humanist Association, said: "What they describe as discrimination and marginalisation of Christians is in fact the proper upholding of human rights and equalities law and principles, and we are pleased that the court has recognised this."