The discovery of Herculaneum in 1738 helped inspire Neoclassicism. Although the buried Roman town had been known since earlier accidental finds, systematic excavation began in 1738 under the direction of engineers working for Charles VII of Naples. The ancient city had been sealed by the eruption of Mount Vesuvius in AD 79, preserving buildings, sculpture, inscriptions, and other Roman material.
Herculaneum’s discoveries arrived during a European revival of interest in Greek and Roman antiquity. Artists, architects, collectors, and theorists studied the excavated remains alongside finds from Pompeii and the writings of Johann Joachim Winckelmann. Their influence encouraged the balanced forms, archaeological references, and restrained ornament associated with Neoclassicism.
A common mix-up is Pompeii, whose major excavations began in 1748 and also strongly shaped Neoclassical art. The date in the question points specifically to Herculaneum: its organized excavation preceded Pompeii’s by a decade. The finds also included the Herculaneum papyri, an extraordinary library carbonized by the eruption.