The modern electric guitar is a distant product compared to its humbler origins, and prior to such modern developments and trends, and the increased use of synthetic materials, a guitar was simply defined as any instrument which had a long neck which was fretted, at the base of which was a soundboard with curved sides, and importantly, had a flat back. This was in contrast to the lute and other similar stringed instruments of early musical development.
Although it may seem that guitars are fairly new, similar instruments which fit the definition have been around, and been very popular, for at least five thousand years. The classical guitar we know today, with its six strings, was developed in Spain originally, although it has a long and diverse history itself, and like many instruments, has a mixed heritage, borrowing as it does from various similar musical trends in instrumentation.
Much of the origin of the Spanish six stringed guitar can be traced back to the Middle East, and in particular central Asia and India, where the sitar and other similar stringed instruments were very popular. In addition to the sitar, which is still popular today and has a very distinctive sound which almost immediately conjured up images of India, the guitar has a heritage which can be traced back to such instruments as the tanbur and the setar which both originate from Iran.
However, these historical origins can be predated still further, and we can take the history of the development of the guitar back to a record which is well over three thousand years old. There is a carving of a Hittite bard holding a stringed instrument which cannot be mistaken for anything other than an early form of a guitar like instrument, which shows that the instrument had already gained a popular role within society. The word sitar and guitar seem very similar, and this is because they both share the same ancestry.
The word guitar comes from the Latin word cithara meaning stringed instrument, and this word in turn comes from Greek heritage. The Greek word, kithara is thought to come from the Persian word sitar, which is where the words guitar and sitar share a lexical ancestor.
The word cithara, the Latin word from which guitar is derived, refers to an ancestor of the modern six string guitar, and was a popular instrument in Roman times, although rather than strummed, it appears to have been plucked, generating a fairly distinctive sound, and one fairly dissimilar to the traditional sound we associate today. In fact, the sound was more likely to be more similar to the Indian or Persian sitar sound quality than the European sound we hear today. The Romans brought their cithara with them to Spain, or Hispania as it was called, sometime in the first century AD, and was later adapted to incorporate some of the style and developments of another stringed instrument, the oud, which was brought by the Moors over six hundred years later. It was at this same time that the lute, popular in Scandinavian countries, was becoming very popular.
The lute has more in common with the six stringed guitar, as it too had the same six strings, although the back of the lute was curved, generating a different acoustic sound. The very well known Viking hero, Gunther, is depicted with a lute, as the Vikings took to the Scandinavian instrument very well, and it has been depicted in many carvings of that era. The oud and the cathira both developed into two guitar like instruments, but with different sounds, resulting in the Moorish guitar which was popular in around the 13th century, and the Latin guitar, which is the one which most closely resembles the guitar we think of today.