A whirlwind romance that began in Los Angeles sealed a place in the British history books this weekend as Sinclair Treadway and Sean Adl-Tabatabai became one of the country’s first gay couples to be legally wed.

They exchanged a pair of simple gold bands in a ceremony that began at 12:01 a.m. on Saturday, the first day same-sex marriages were allowed in Britain. Treadway’s parents, who flew in from the U.S. for the celebration, were among 100 guests crowded into Camden town hall in North London.

With the British Prime Minister among those offering congratulations, Treadway, 20, from Simi Valley, California, said it had been an overwhelming experience just one year after he met his partner in the U.S. “It’s all happened too quickly it's hard to take it in, but I am just so thrilled and amazed that our wedding is so important not just to us but to the rest of England and Wales and the world,” he said.

The ceremony was led by the mayor of Camden, Jonathan Simpson. He said, “As an active member of the LGBT community it was an honor and a privilege to be part of Sean and Sinclair's happy day.”

Couples all over the country were saying “I do” as the clock struck midnight with ceremonies planned throughout the day. Prime Minister Cameron sent his regards to all of the happy couples. "Congratulations to the gay couples who have already been married—and my best wishes to those about to be on this historic day,” he wrote on Twitter.

A bill legalizing gay marriage was passed by the Houses of Parliament last year, allowing the weddings to take place ten years after same-sex civil partnerships were ushered into British law. The leaders of the three main political parties have all offered their support to the introduction of gay marriages.

The Church of England, which has been opposed to same-sex unions for five centuries, remains split on the issue but the Archbishop of Canterbury conceded that the church’s evolution on the issue had been overtaken by events. "The law's changed; we accept the situation," he told the BBC.

Londoners John Coffey and Bernardo Marti also raced to be married as soon as it was legally possible. Their ceremony in Westminster began at 11.30pm on Friday night allowing the registrar to pronounce them “husband and husband” as soon after midnight as possible.

Coffey told the Press Association it was an “extraordinary” feeling to be married, something he thought could never happen. “The ceremony completely exceeded our expectations as well. We were scared coming into this through nerves and there has been a lot of media attention, but we both came here and I think our love carried us through in the end.”