Portugal's conservative president said he is reluctantly ratifying a law allowing gay marriage, making the predominantly Roman Catholic country the sixth in Europe to let same-sex couples wed.
President Anibal Cavaco Silva said he would not veto the bill because majority liberal politicians would only overturn his decision.
The country must focus instead on battling a crippling economic crisis that has increased unemployment and deepened poverty, he said.
"Given that fact, I feel I should not contribute to a pointless extension of this debate, which would only serve to deepen the divisions between the Portuguese and divert the attention of politicians away from the grave problems affecting us," Mr Cavaco Silva said.
He said he was setting aside his "personal convictions," though he did not elaborate and did not take reporters' questions.
The country's parliament passed the Socialist government-backed bill in January, with the support of all of Portugal's left-of-centre parties, who together have a majority. Right-of-centre parties opposed the measure and demanded a national referendum.
Elsewhere in Europe, gay marriage is permitted in Belgium, the Netherlands, Spain, Sweden and Norway.
As well, five US states and Washington, DC, legalised same-sex marriage, as have Canada and South Africa.
Mr Cavaco Silva's announcement came three days after Pope Benedict XVI left Portugal. During his four-day visit, which attracted hundreds of thousands of people, the pontiff said same-sex marriage and abortion were some of the most "insidious and dangerous" threats facing the world.
Socialist Party spokesman Vitalino Canas welcomed the president's decision.
"This is a memorable moment," he said. "This is a great step forward for us politically and as a society."
Antonio Serzedelo, the president of lobbying group Opus Gay, congratulated the head of state for placing "ethical responsibility above personal opinions".
Portugal is nearly 90% Catholic. However, only around two million of its 10.6 million people describe themselves as practising Catholics and Portugal has drifted away from the church's teachings.
The current Socialist government has defied the church before. It passed a law in 2007 allowing abortions. The following year, it introduced a law allowing divorce even if one of the spouses objected. It has argued that the legislation is part of Portugal's "modernisation".
The new law removes the previous legal stipulation that marriage is between two people of different sexes.
Portugal's Constitutional Court validated the bill's legality last month.