When was the first exoplanet discovered?

In 1995, astronomers Michel Mayor and Didier Queloz announced the discovery of 51 Pegasi b, the first planet found orbiting a Sun-like star. They detected it using the radial velocity method, which measures tiny wobbling motions in the star caused by an orbiting planet. The planet was unlike anything expected at the time because it was a gas giant very close to its star. The discovery transformed astronomy by showing that planets outside our Solar System are common. Mayor and Queloz received the 2019 Nobel Prize in Physics for this work.