Here are some possibilities:
* Johann Sebastian Bach: While Bach's music has elements of what we would consider "Romantic" (emotionality, complex harmonies), he lived and composed in the Baroque period (1600-1750).
* Wolfgang Amadeus Mozart: Mozart straddled the line between Classical and Romantic eras. While his music is considered Classical, it has elements that foreshadowed Romanticism.
* Ludwig van Beethoven: Beethoven is often considered a bridge between the Classical and Romantic periods. His late works, particularly his symphonies, are highly Romantic.
* Any composer from the Classical era (c. 1750-1820): The Romantic era is generally considered to have started around 1820, so any composer from the Classical era, like Haydn, Mozart, or even early Beethoven, would not be considered Romantic.
Therefore, the most definitive answer depends on how you define the Romantic era and which composer you're focusing on.