Except for the organ, the piano is the most complex of any musical instrument. In fact, its proper name is the pianoforte, which means “soft-strong.” This is because the piano is capable of a variety of tones.

Yet the piano grew from a very simple instrument called a monochord. This was a box with a single string which had the intervals of the scale marked off on it.

About the year 1000 A.D., a man named Guido d’Arezzo invented a movable bridge for the monochord and added keys and more strings. This new instrument he created was in use until the sixteenth century. Later on it took another form—the clavichord. The sound in the clavichord is produced by the vibration of strings through the pressure of a brass pin flattened on top.

A closely related instrument was the spinet. It was an oblong instrument with a compass of four octaves. Its strings were set in motion by picking or twanging.

A well-known instrument of the seventeenth century was the harp sichord. It is larger than either the clavichord or the spinet and generally has two keyboards. It is shaped like a grand piano. Its strings are twanged by tiny quills.

The really big difference which set the piano apart from such instruments was the hammer action. This was the creation of Bartolommeo Christofori in 1709. The hammer action did away forever with the scratching sound which could not be avoided in the more primitive instruments.

By the time of Mozart and Beethoven, the pianoforte had become the popular keyboard instrument we know today. Beethoven was the first composer to bring about greater use of the piano, his music often calling for the lower, richer tones of the piano.