In silents, the phrase "came the dawn" serves as a fancy way of signifying that it is now morning. "It is now morning" certainly seems a little lackluster by comparison. Despite all claims that it was the most famous title card ever (even Alfred Hitchcock says so), I have never seen it appear in an actual movie.
British film director Cecil Hepworth wrote an autobiography entitled Came the Dawn. In it, he gives advice that was common in the silent period - don't include too much text in movies. Let the images tell the story. Specifically, he says never to use the phrase "came the dawn."
From a 1924 issue of Life. Even by then the phrase seems to have become a cliche.
Liberty Magazine makes this claim in a 1927 article. Clawson wrote dozens of screenplays - so it may be true - but he is never credited with writing a title card.
You cannot beat the Little Rascals for biting social commentary. Hal Roach also made Came the Yawn in 1928.
A quick google search mostly points to this comic by Wallace Wood and Al Feldstein. It is sort of a precursor to Sin City. The phrase appears in other odd areas as well, including this Marvin Gaye song and in the name of this emo screamcore band. In some contexts, it appears to signify "and then it dawned on me," or "there is always tomorrow." In other contexts (such as the comic above), it suggests that life goes on, even if that life is horrible.
This is a bit like Benjamin's Arcades Project, but on a much smaller scale. Intertitles, subtitles, books with images, and other monstrous hybrids.