Pioneer 10 was launched in 1972 and beat both Voyagers out of the Solar System. P10 exited circa 2003.
The Voyagers traveling faster have overtaken both Pioneer craft. I think Pioneer 10 was the first beyond Pluto and at the time, little to nothing was known about the sun's influence beyond Pluto. Now, more is known and I believe what Voyager just did was pass the farthest known influence of our solar system.