It's latin. "de omnibus" on the second line is pretty well recognizable. But holy hell is Gutenberg's font terrible. Look at the first word on the second line, it ends in seven undotted sticks that seem to bleed over into each other a bit. I read that as "mim" before I figured out it was "num".

Anyway, it's the Gutenberg bible. The epistle of St. Jerome, according to the alt text.