It defined it self in opposition to Modernism, but it was always there.
I repsectfully disagree. But this is not the forum to fully air my disagreement, except to note:
G. Gresham Machen rejected the label though he otherwise qualified for it. Machen based his decision on the premise that he was only being an orthodox Presbyterian. Though I don't mind the label, my theological positions are those of Historic Northern Baptist. I.e., we were Fundamentalists before Fundamentalism was fun.
Please read. Francis Wayland's
Notes on the Principles and Practices of Baptist Churches and Edward Thurston
Hiscox's New Directory for Baptist Churches. NP&P was complied in 1856 and Hiscox's New Directory was published in 1894. Both are authoritative and were written before the Modernist controversy took off.
Both are available in digital format through Google Books.