Finally, circa 1850, the form and structure of the modern guitar are followed by different Spanish makers such as Manuel de Soto y Solares and perhaps the most important of all guitar makers Antonio Torres Jurado, who increased the size of the guitar body, altered its proportions, and invented the breakthrough fan-braced pattern. Bracing, which refers to the internal pattern of wood reinforcements used to secure the guitar's top and back and prevent the instrument from collapsing under tension, is an important factor in how the guitar sounds. Torres' design greatly improved the volume, tone, and projection of the instrument, and it has remained essentially unchanged since.