20th-century Recoveries
The number of asteroids that were only observed once and not re-observed grew throughout the 19th and 20th centuries, but improved telescopes, searches, and detection techniques led to most of these cases being resolved in the 1970s, 80s, and 90s. There are earlier examples also, such as 132 Aethra, which was lost between 1873 and 1922.
Read more about this topic: Lost Asteroid