MPs voted in favour of the Marriage (Same Sex Couples) Bill by 400 to 175, a majority of 225.
I'm going to post a few pictures, together with quotes from the MPs that made this change happen.
The Prime Minister pushed this crucial piece of legislation through against many of his party. This may affect his career. This may affect his re-election. Whatever happens, Mr Cameron, I salute you for recognising and trying to change the injustice that affects LGBT people.
David Cameron says he is proud that love between a same-sex couple will now "count the same" as a heterosexual couple, despite almost half his MPs voting against gay marriage.
"Marriage is one of the most important institutions we have, it binds society and families together, it is a building block that promotes stability. This bill supports and cultivates marriage." Maria Miller, Minister for Women and Equalities
"We have come a long way in a short space of time but it is absolutely right we take the next step and delivers full legal equality for lesbian, gay and bisexual people in our country. This view is one that is borne of a hatred of discrimination and prejudice of all types, whether it's about gender or skin colour or religion." Stephen Gilbert, Liberal Democrat
There was the usual objections to equal marriage. Marriage shouldn't be redefined. Yeah, despite the fact that it's been redefined over and over again.
"If marriage hadn't been re-defined in 1836, there wouldn't be any civil marriages; if it hadn't been re-defined in 1949, under 16-year-olds would still be able to get married; if it hadn't been re-defined in 1969, we wouldn't have today's divorce laws - and all of these changes were opposed." Nick Herbert, Conservative.
There were the usual arguments that you have Civil Partnerships so why do you need marriage?
"There are still those who say this is all unnecessary. Why do we need gay marriage when we already have civil partnership, they say. They are the same - separate but equal - they claim. Let me speak frankly - separate but equal is a fraud. Separate but equal is the language that tried to push Rosa Parks to the back of the bus. Separate but equal is the motif that determined that black and white people could not possibly drink from the same water fountain, eat at the same table or use the same toilets. It is an excerpt from the phrasebook of the segregationist and the racists. This is not separate but equal it is separate and discriminated, separate and oppressed, separate and brow beaten, separate and subjugated. Separate is not equal so let us be rid of it." David Lammy, Labour.
For me Yvette Cooper, the shadow minister for women and equalities, said it all.
"Call us hopeless romantics, call it the triumph of hope over experience - most of us think when people love each other and want to make that long-term commitment, that is a wonderful thing. So why would we stop a loving couple getting married just because they are gay?"
For more information about same sex marriage, here is a Q&A on the BBC site.