That's a tricky question. Essentially, the 12 bar blues progression is a I chord, a IV chord, and a V chord. I, IV, and V are the most important chords to establish tonality, so they've been used together since pretty much the beginning of western music. The simple matter of doing 4 bars of I, 2 bars of IV, 2 bars of I, 2 bars of V, and 2 bars of I is not particularly important to the fact that the chord progression is simply the tonic, subdominant, and dominant chords. Musical phrases tend to run in four bar phrases naturally (also basically forever), so it's not too surprising that the blues would evolve from a multiple of four bars.

Ragtime is possibly the most obvious predecessor to blues and jazz. And this was a mid to late 19th century musical style. Scott Joplin is the most famous composer in this style.

But it probably isn't until Dixieland jazz that you might first hear music that you can associate with the blues. This was the early 20th century. Influenced by riverboat jazz, Dixieland is extremely similar to the marching band music made most famous by John Philip Sousa. I've never heard riverboat jazz, but there are many recordings of Dixieland. Check out the music of Louis Armstrong and his Hot Five or Hot Seven bands. Also make sure you listen to Bessie Smith from the 1920's as one of the first really great blues singers.

The spiritual music of African-Americans played a big role in the overall development of what became blues, jazz, and rock music. Unfortunately, there isn't a lot of written record on this music. It's nature is in an aural tradition, and literacy was uncommon among slaves (much less musical literacy in a western sense).

So short answer, the chord progression is ancient. But the chord progression is not what defines the blues sound that we are familiar with. This is possibly first heard with ragtime, but not until the 20th century would we really recognize it as "blues".