On December 30, 1968, The Spokesman-Review of Spokane, Washington, ran an advertisement for a concert at Gonzaga University featuring “The Vanilla Fudge, with Len Zefflin”—a concert of which a bootleg recording would later emerge that represents the first-ever live Led Zeppelin performance captured on tape.

Within a year, they’d be big. Within two, they’d be huge. And within three, they’d be the biggest band in the world. But on that date, the quartet of British rockers preparing for their fifth-ever gig in the United States were using propane heaters to keep themselves and their equipment warm while they waited to go on as the opening act for Vanilla Fudge at a concert in a frigid college gymnasium in Washington State. A few serious rock fans in attendance had at least heard about the new band formed around the former guitarist from the now-defunct Yardbirds, but if those fans even knew the name of this new group, they might not have recognized it in the ads that ran in the local newspaper.

At the end of the now widely available recording known as Gonzaga ’68, Robert Plant can be heard introducing himself and his bandmates—John Paul Jones on bass, Jimmy Page on guitar and John Bonham on drums—to a smattering of applause. But some of those who were in attendance that day remember their reaction as being stronger. In a Spokesman-Review article published 29 years after the night in question, Bob Gallagher, a teenage record-store employee at the time, recalled the show’s opening number: “”Bonham came out and started drumming on ‘Train Kept a-Rollin’,” Gallagher said, “and everybody went, ‘Holy crap.'”

There is nothing raw or un-Led Zeppelin-like about the sound captured by an unknown Gonzaga student on a small, portable tape recorder that day. The Gonzaga ’68 bootleg features the band performing tight and thrilling versions of some songs that are now considered classics but were then unknown to those in attendance. Indeed, halfway through the set, Robert Plant introduces one number as follows: “This is off an album that comes out in about three weeks time on the Atlantic label. It’s called Led Zeppelin. This is a tune called ‘Dazed and Confused.'”