Why did string sections grow larger in 19th-century symphony orchestras?

During the 19th century, the size of symphony orchestras expanded significantly as composers sought to create larger, more complex, and more expressive musical works. This growth was driven by the Romantic era's emphasis on instrumental color and the desire for greater tonal resources to convey programmatic ideas and intense emotional depth.12

As composers like Hector Berlioz, Richard Wagner, and later Gustav Mahler and Richard Strauss pushed the boundaries of orchestration, they demanded larger forces to achieve their artistic visions. This expansion was not limited to the string section; wind and brass sections were also augmented to provide a more powerful and versatile sound palette. By the late 19th century, it was common for a symphony orchestra to incorporate approximately 100 performers to meet the requirements of these increasingly ambitious compositions. This shift toward larger ensembles allowed for a wider range of dynamics and textures, establishing the modern concept of the large-scale symphony orchestra.12