What work was the start of musical romanticism?

The start of musical Romanticism is often attributed to Ludwig van Beethoven, particularly with his later works, such as his Symphony No. 5 and the "Moonlight" Sonata. These compositions emphasized individual expression, emotional depth, and innovative structures, setting the stage for the Romantic movement. Beethoven's ability to convey personal feelings and dramatic narratives through music inspired subsequent composers to explore similar themes, marking a significant shift from the Classical era's focus on form and balance.