When President Obama said Monday that “our journey is not complete until our gay brothers and sisters are treated like anyone else under the law,” he made history by becoming the first president to advocate for gay rights in an inaugural address.

The remark was a reflection of shifting attitudes toward the issue of gay marriage. It was also a reminder of how far the president’s own position has moved.

It wasn’t too long ago that Obama, who now favors the right of same-sex couples to marry, was only in favor of civil unions. The Daily Beast published a useful chronological rundown of Obama’s positions last year, dating back to his 2004 Senate campaign.

Then, state senator Obama declared that he didn’t think marriage was "a civil right,” but that “not being discriminated against is a civil right." As the piece also notes, Obama said in the 2008 presidential campaign that he believed marriage is the "union between a man and a woman."

After saying that his views on gay marriage were “evolving,” Obama drew praise from gay rights advocates when he endorsed granting same-sex couples the right to marry last May.

“You know, Malia and Sasha, they have friends whose parents are same-sex couples. There have been times where Michelle and I have been sitting around the dinner table and we’re talking about their friends and their parents and Malia and Sasha, it wouldn’t dawn on them that somehow their friends’ parents would be treated differently,” Obama said at the time in an interview with ABC News. “It doesn’t make sense to them and, frankly, that’s the kind of thing that prompts a change in perspective.”

On Monday, Obama mentioned the 1969 Stonewall gay rights riot in the same sentence Monday as the civil rights marches in Selma, Ala., and the Seneca Falls, N.Y., women’s rights convention.

“We the people declare today that the most evident of truth that all of us are created equal -- is the star that guides us still; just as it guided our forebears through Seneca Falls and Selma and Stonewall; just as it guided all those men and women, sung and unsung, who left footprints along this great mall, to hear a preacher say that we cannot walk alone; to hear a King proclaim that our individual freedom is inextricably bound to the freedom of every soul on Earth,” the president said.

Mentioning those three events in the same breath is particularly notable for a pol who once said he didn’t think marriage was a civil right.

Obama’s latest remarks come at a point gay rights advocates see as a pivotal moment. Maine, Maryland and Washington state all passed new gay marriage laws last November, and Minnesota voters defeated a ban. Polling shows the public is mostly in favor of legalizing gay marriage.

Expect to hear more about the issue of gay rights from future Democratic presidential candidates. (National Journal's Reid Wilson called it the “new Democratic litmus test.") Just look at the crop of potential 2016 contenders: New York Gov. Andrew Cuomo and Maryland Gov. Martin O’Malley both spearheaded gay marriage laws in their state, while Vice President Biden said he was “absolutely comfortable” with same-sex marriage, even before Obama did.

In his Monday speech, Obama tended toward the general, not the specific, which is typical of inaugural addresses. But make no mistake: On the issue of gay rights, the president opted to make a real statement by wading in deeper.

-- Alice Crites contributed