The first asteroid ever discovered was Ceres.
Giuseppe Piazzi discovered Ceres on January 1, 1801, while observing from Palermo, Sicily. He initially thought the moving object might be a comet, but its slow, star-like motion suggested that it could be something entirely new. The discovery filled part of the expected gap between Mars and Jupiter, where some astronomers believed another planet might orbit.
Ceres was initially announced as a planet and retained that status in many astronomical catalogs for decades. After Pallas, Juno and Vesta were found in the same broad region, astronomers recognized that these bodies formed a new population. William Herschel proposed the term “asteroid,” meaning star-like, for such objects.
Ceres is now classified both as an asteroid and as a dwarf planet. It is the largest object in the main asteroid belt and the only officially recognized dwarf planet located there. A common mix-up is Vesta, which is one of the largest and brightest asteroids, but it was discovered later, in 1807. NASA’s Dawn spacecraft orbited Ceres from 2015 to 2018.